21293047256 has 32 divisors (see below), whose sum is σ = 44044257600. Its totient is φ = 9587861760.

The previous prime is 21293047241. The next prime is 21293047271. The reversal of 21293047256 is 65274039212.

It is an interprime number because it is at equal distance from previous prime (21293047241) and next prime (21293047271).

It is a super-2 number, since 2×21293047256² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2492576 + ... + 2501103.

It is an arithmetic number, because the mean of its divisors is an integer number (1376383050).

Almost surely, 2^21293047256 is an apocalyptic number.

21293047256 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21293047256 is an abundant number, since it is smaller than the sum of its proper divisors (22751210344).

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

21293047256 is a wasteful number, since it uses less digits than its factorization.

21293047256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4993739 (or 4993735 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 41.

The spelling of 21293047256 in words is "twenty-one billion, two hundred ninety-three million, forty-seven thousand, two hundred fifty-six".