21620418 has 16 divisors (see below), whose sum is σ = 43424640. Its totient is φ = 7176176.

The previous prime is 21620411. The next prime is 21620419. The reversal of 21620418 is 81402612.

It is not an unprimeable number, because it can be changed into a prime (21620411) 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, 6105 + ... + 8972.

It is an arithmetic number, because the mean of its divisors is an integer number (2714040).

Almost surely, 2^21620418 is an apocalyptic number.

21620418 is an abundant number, since it is smaller than the sum of its proper divisors (21804222).

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

21620418 is a wasteful number, since it uses less digits than its factorization.

21620418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15321.

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21620418 is about 4649.7761236429. The cubic root of 21620418 is about 278.5830541969.

The spelling of 21620418 in words is "twenty-one million, six hundred twenty thousand, four hundred eighteen".