21669438 has 32 divisors (see below), whose sum is σ = 51240960. Its totient is φ = 5977440.

The previous prime is 21669371. The next prime is 21669493. The reversal of 21669438 is 83496612.

It is a junction number, because it is equal to n+sod(n) for n = 21669396 and 21669405.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 7678 + ... + 10113.

It is an arithmetic number, because the mean of its divisors is an integer number (1601280).

Almost surely, 2^21669438 is an apocalyptic number.

21669438 is an abundant number, since it is smaller than the sum of its proper divisors (29571522).

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

21669438 is a wasteful number, since it uses less digits than its factorization.

21669438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17832.

The product of its digits is 62208, while the sum is 39.

The square root of 21669438 is about 4655.0443606909. The cubic root of 21669438 is about 278.7934391740.

The spelling of 21669438 in words is "twenty-one million, six hundred sixty-nine thousand, four hundred thirty-eight".