21277256 has 64 divisors (see below), whose sum is σ = 53585280. Its totient is φ = 7649280.

The previous prime is 21277247. The next prime is 21277261. The reversal of 21277256 is 65277212.

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, 6680 + ... + 9336.

It is an arithmetic number, because the mean of its divisors is an integer number (837270).

Almost surely, 2^21277256 is an apocalyptic number.

21277256 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21277256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26792640).

21277256 is an abundant number, since it is smaller than the sum of its proper divisors (32308024).

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

21277256 is a wasteful number, since it uses less digits than its factorization.

21277256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2694 (or 2690 counting only the distinct ones).

The product of its digits is 11760, while the sum is 32.

The square root of 21277256 is about 4612.7276095603. The cubic root of 21277256 is about 277.1012849294.

The spelling of 21277256 in words is "twenty-one million, two hundred seventy-seven thousand, two hundred fifty-six".