221572764 has 72 divisors (see below), whose sum is σ = 677765088. Its totient is φ = 59581440.

The previous prime is 221572763. The next prime is 221572829. The reversal of 221572764 is 467275122.

It is a happy number.

221572764 is a `hidden beast` number, since 2 + 21 + 572 + 7 + 64 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221572763) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21577 + ... + 30144.

It is an arithmetic number, because the mean of its divisors is an integer number (9413404).

Almost surely, 2^221572764 is an apocalyptic number.

It is an amenable number.

221572764 is an abundant number, since it is smaller than the sum of its proper divisors (456192324).

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

221572764 is a wasteful number, since it uses less digits than its factorization.

221572764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51755 (or 51750 counting only the distinct ones).

The product of its digits is 47040, while the sum is 36.

The square root of 221572764 is about 14885.3204197961. The cubic root of 221572764 is about 605.1162165467.

It can be divided in two parts, 221 and 572764, that added together give a triangular number (572985 = T₁₀₇₀).

The spelling of 221572764 in words is "two hundred twenty-one million, five hundred seventy-two thousand, seven hundred sixty-four".