21907692 has 48 divisors (see below), whose sum is σ = 57349600. Its totient is φ = 7231680.

The previous prime is 21907643. The next prime is 21907693. The reversal of 21907692 is 29670912.

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 (21907693) 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, 10842 + ... + 12702.

Almost surely, 2^21907692 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21907692, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28674800).

21907692 is an abundant number, since it is smaller than the sum of its proper divisors (35441908).

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

21907692 is a wasteful number, since it uses less digits than its factorization.

21907692 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1983 (or 1975 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 21907692 is about 4680.5653504678. The cubic root of 21907692 is about 279.8114887587.

The spelling of 21907692 in words is "twenty-one million, nine hundred seven thousand, six hundred ninety-two".