21623404 has 36 divisors (see below), whose sum is σ = 43200360. Its totient is φ = 9391360.

The previous prime is 21623389. The next prime is 21623411. The reversal of 21623404 is 40432612.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22812 + ... + 23740.

It is an arithmetic number, because the mean of its divisors is an integer number (1200010).

Almost surely, 2^21623404 is an apocalyptic number.

It is an amenable number.

21623404 is a deficient number, since it is larger than the sum of its proper divisors (21576956).

21623404 is a wasteful number, since it uses less digits than its factorization.

21623404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990 (or 965 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 21623404 is about 4650.0972032851. The cubic root of 21623404 is about 278.5958786592.

The spelling of 21623404 in words is "twenty-one million, six hundred twenty-three thousand, four hundred four".