21358404 has 30 divisors (see below), whose sum is σ = 55835934. Its totient is φ = 7119360.

The previous prime is 21358399. The next prime is 21358429. The reversal of 21358404 is 40485312.

It can be written as a sum of positive squares in only one way, i.e., 12960000 + 8398404 = 3600^2 + 2898^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 32637 + ... + 33284.

Almost surely, 2^21358404 is an apocalyptic number.

It is an amenable number.

21358404 is an abundant number, since it is smaller than the sum of its proper divisors (34477530).

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

21358404 is a wasteful number, since it uses less digits than its factorization.

21358404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65937 (or 65926 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 21358404 is about 4621.5153359044. The cubic root of 21358404 is about 277.4531111427.

The spelling of 21358404 in words is "twenty-one million, three hundred fifty-eight thousand, four hundred four".