21690522 has 24 divisors (see below), whose sum is σ = 53710176. Its totient is φ = 6197256.

The previous prime is 21690499. The next prime is 21690523. The reversal of 21690522 is 22509612.

It is not an unprimeable number, because it can be changed into a prime (21690523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 85948 + ... + 86199.

It is an arithmetic number, because the mean of its divisors is an integer number (2237924).

Almost surely, 2^21690522 is an apocalyptic number.

21690522 is an abundant number, since it is smaller than the sum of its proper divisors (32019654).

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

21690522 is a wasteful number, since it uses less digits than its factorization.

21690522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172162 (or 172159 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 21690522 is about 4657.3084501673. The cubic root of 21690522 is about 278.8838303119.

The spelling of 21690522 in words is "twenty-one million, six hundred ninety thousand, five hundred twenty-two".