221509152 has 54 divisors (see below), whose sum is σ = 630635733. Its totient is φ = 73752192.

The previous prime is 221509147. The next prime is 221509157. The reversal of 221509152 is 251905122.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

221509152 is a `hidden beast` number, since 2 + 2 + 1 + 509 + 152 = 666.

221509152 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (221509147) and next prime (221509157).

It can be written as a sum of positive squares in 2 ways, for example, as 191434896 + 30074256 = 13836^2 + 5484^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=10524.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (221509157) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 252138 + ... + 253014.

Almost surely, 2^221509152 is an apocalyptic number.

It is an amenable number.

221509152 is an abundant number, since it is smaller than the sum of its proper divisors (409126581).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221509152 is an frugal number, since it uses more digits than its factorization.

221509152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1770 (or 882 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 221509152 is about 14883.1835304145. The cubic root of 221509152 is about 605.0583027846.

Multiplying 221509152 by its product of nonzero digits (1800), we get a square (398716473600 = 631440²).

The spelling of 221509152 in words is "two hundred twenty-one million, five hundred nine thousand, one hundred fifty-two".