21477312 has 84 divisors (see below), whose sum is σ = 63887096. Its totient is φ = 7153920.

The previous prime is 21477301. The next prime is 21477343. The reversal of 21477312 is 21377412.

It is a happy number.

It is a super-2 number, since 2×21477312² = 922549861490688, which contains 22 as substring.

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

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 11 ways as a sum of consecutive naturals, for example, 14862 + ... + 16242.

Almost surely, 2^21477312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21477312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31943548).

21477312 is an abundant number, since it is smaller than the sum of its proper divisors (42409784).

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

21477312 is an equidigital number, since it uses as much as digits as its factorization.

21477312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1408 (or 1386 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 21477312 is about 4634.3620920252. The cubic root of 21477312 is about 277.9670440377.

The spelling of 21477312 in words is "twenty-one million, four hundred seventy-seven thousand, three hundred twelve".