21063256 has 8 divisors (see below), whose sum is σ = 39493620. Its totient is φ = 10531624.

The previous prime is 21063253. The next prime is 21063257. The reversal of 21063256 is 65236012.

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21063256.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21063253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1316446 + ... + 1316461.

Almost surely, 2^21063256 is an apocalyptic number.

It is an amenable number.

21063256 is a deficient number, since it is larger than the sum of its proper divisors (18430364).

21063256 is a wasteful number, since it uses less digits than its factorization.

21063256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2632913 (or 2632909 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21063256 is about 4589.4723008207. The cubic root of 21063256 is about 276.1691534678.

Adding to 21063256 its reverse (65236012), we get a palindrome (86299268).

The spelling of 21063256 in words is "twenty-one million, sixty-three thousand, two hundred fifty-six".