21427256 has 16 divisors (see below), whose sum is σ = 41156640. Its totient is φ = 10452160.

The previous prime is 21427247. The next prime is 21427271. The reversal of 21427256 is 65272412.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32336 + ... + 32991.

It is an arithmetic number, because the mean of its divisors is an integer number (2572290).

Almost surely, 2^21427256 is an apocalyptic number.

It is an amenable number.

21427256 is a deficient number, since it is larger than the sum of its proper divisors (19729384).

21427256 is a wasteful number, since it uses less digits than its factorization.

21427256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65374 (or 65370 counting only the distinct ones).

The product of its digits is 6720, while the sum is 29.

The square root of 21427256 is about 4628.9584141576. The cubic root of 21427256 is about 277.7509285101.

Adding to 21427256 its reverse (65272412), we get a palindrome (86699668).

The spelling of 21427256 in words is "twenty-one million, four hundred twenty-seven thousand, two hundred fifty-six".