221306690 has 32 divisors (see below), whose sum is σ = 453465216. Its totient is φ = 76975360.

The previous prime is 221306689. The next prime is 221306693. The reversal of 221306690 is 96603122.

221306690 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 a super-2 number, since 2×221306690² = 97953302077512200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (221306693) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41207 + ... + 46266.

It is an arithmetic number, because the mean of its divisors is an integer number (14170788).

Almost surely, 2^221306690 is an apocalyptic number.

221306690 is an abundant number, since it is smaller than the sum of its proper divisors (232158526).

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

221306690 is a wasteful number, since it uses less digits than its factorization.

221306690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87514.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 221306690 is about 14876.3802720958. The cubic root of 221306690 is about 604.8739030965.

The spelling of 221306690 in words is "two hundred twenty-one million, three hundred six thousand, six hundred ninety".