21607992 has 128 divisors (see below), whose sum is σ = 70963200. Its totient is φ = 5961600.

The previous prime is 21607991. The next prime is 21608029. The reversal of 21607992 is 29970612.

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 (21607991) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 46642 + ... + 47102.

It is an arithmetic number, because the mean of its divisors is an integer number (554400).

Almost surely, 2^21607992 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 21607992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35481600).

21607992 is an abundant number, since it is smaller than the sum of its proper divisors (49355208).

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

21607992 is a wasteful number, since it uses less digits than its factorization.

21607992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514 (or 504 counting only the distinct ones).

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

The square root of 21607992 is about 4648.4397382348. The cubic root of 21607992 is about 278.5296735388.

The spelling of 21607992 in words is "twenty-one million, six hundred seven thousand, nine hundred ninety-two".