21642372 has 36 divisors (see below), whose sum is σ = 55875456. Its totient is φ = 7060080.

The previous prime is 21642367. The next prime is 21642389. The reversal of 21642372 is 27324612.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4704 + ... + 8087.

It is an arithmetic number, because the mean of its divisors is an integer number (1552096).

Almost surely, 2^21642372 is an apocalyptic number.

It is an amenable number.

21642372 is an abundant number, since it is smaller than the sum of its proper divisors (34233084).

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

21642372 is a wasteful number, since it uses less digits than its factorization.

21642372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12848 (or 12843 counting only the distinct ones).

The product of its digits is 4032, while the sum is 27.

The square root of 21642372 is about 4652.1362834724. The cubic root of 21642372 is about 278.6773160718.

Adding to 21642372 its reverse (27324612), we get a palindrome (48966984).

The spelling of 21642372 in words is "twenty-one million, six hundred forty-two thousand, three hundred seventy-two".