21690168 has 16 divisors (see below), whose sum is σ = 54225480. Its totient is φ = 7230048.

The previous prime is 21690157. The next prime is 21690169. The reversal of 21690168 is 86109612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21690169) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 451855 + ... + 451902.

Almost surely, 2^21690168 is an apocalyptic number.

It is an amenable number.

21690168 is an abundant number, since it is smaller than the sum of its proper divisors (32535312).

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

21690168 is a wasteful number, since it uses less digits than its factorization.

21690168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 903766 (or 903762 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21690168 is about 4657.2704452286. The cubic root of 21690168 is about 278.8823131298.

The spelling of 21690168 in words is "twenty-one million, six hundred ninety thousand, one hundred sixty-eight".