21265902 has 144 divisors (see below), whose sum is σ = 59754240. Its totient is φ = 5633712.

The previous prime is 21265897. The next prime is 21265913. The reversal of 21265902 is 20956212.

21265902 is a `hidden beast` number, since 2 + 1 + 2 + 659 + 0 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 452443 + ... + 452489.

It is an arithmetic number, because the mean of its divisors is an integer number (414960).

Almost surely, 2^21265902 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21265902, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29877120).

21265902 is an abundant number, since it is smaller than the sum of its proper divisors (38488338).

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

21265902 is a wasteful number, since it uses less digits than its factorization.

21265902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97 (or 78 counting only the distinct ones).

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

The square root of 21265902 is about 4611.4967201550. The cubic root of 21265902 is about 277.0519870972.

The spelling of 21265902 in words is "twenty-one million, two hundred sixty-five thousand, nine hundred two".