21915402 has 16 divisors (see below), whose sum is σ = 44900352. Its totient is φ = 7126880.

The previous prime is 21915391. The next prime is 21915407. The reversal of 21915402 is 20451912.

It is not an unprimeable number, because it can be changed into a prime (21915407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44298 + ... + 44789.

It is an arithmetic number, because the mean of its divisors is an integer number (2806272).

Almost surely, 2^21915402 is an apocalyptic number.

21915402 is an abundant number, since it is smaller than the sum of its proper divisors (22984950).

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

21915402 is a wasteful number, since it uses less digits than its factorization.

21915402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89133.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 21915402 is about 4681.3888964708. The cubic root of 21915402 is about 279.8443097050.

The spelling of 21915402 in words is "twenty-one million, nine hundred fifteen thousand, four hundred two".