21159256 has 8 divisors (see below), whose sum is σ = 39673620. Its totient is φ = 10579624.

The previous prime is 21159247. The next prime is 21159263. The reversal of 21159256 is 65295112.

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

It is a super-2 number, since 2×21159256² = 895428228947072, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1322446 + ... + 1322461.

Almost surely, 2^21159256 is an apocalyptic number.

It is an amenable number.

21159256 is a deficient number, since it is larger than the sum of its proper divisors (18514364).

21159256 is a wasteful number, since it uses less digits than its factorization.

21159256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2644913 (or 2644909 counting only the distinct ones).

The product of its digits is 5400, while the sum is 31.

The square root of 21159256 is about 4599.9191297239. The cubic root of 21159256 is about 276.5880830346.

The spelling of 21159256 in words is "twenty-one million, one hundred fifty-nine thousand, two hundred fifty-six".