21477906 has 32 divisors (see below), whose sum is σ = 49806720. Its totient is φ = 6847632.

The previous prime is 21477889. The next prime is 21477913. The reversal of 21477906 is 60977412.

It is a happy number.

It is a super-2 number, since 2×21477906² = 922600892289672, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7405 + ... + 9888.

It is an arithmetic number, because the mean of its divisors is an integer number (1556460).

Almost surely, 2^21477906 is an apocalyptic number.

21477906 is an abundant number, since it is smaller than the sum of its proper divisors (28328814).

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

21477906 is a wasteful number, since it uses less digits than its factorization.

21477906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17327 (or 17321 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 21477906 is about 4634.4261780721. The cubic root of 21477906 is about 277.9696066008.

The spelling of 21477906 in words is "twenty-one million, four hundred seventy-seven thousand, nine hundred six".