21054256 has 10 divisors (see below), whose sum is σ = 40792652. Its totient is φ = 10527120.

The previous prime is 21054247. The next prime is 21054259. The reversal of 21054256 is 65245012.

It is a self number, because there is not a number n which added to its sum of digits gives 21054256.

It is not an unprimeable number, because it can be changed into a prime (21054259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 657930 + ... + 657961.

Almost surely, 2^21054256 is an apocalyptic number.

It is an amenable number.

21054256 is a deficient number, since it is larger than the sum of its proper divisors (19738396).

21054256 is a wasteful number, since it uses less digits than its factorization.

21054256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1315899 (or 1315893 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 21054256 is about 4588.4916911770. The cubic root of 21054256 is about 276.1298136102.

Adding to 21054256 its reverse (65245012), we get a palindrome (86299268).

The spelling of 21054256 in words is "twenty-one million, fifty-four thousand, two hundred fifty-six".