21581301271256 has 32 divisors (see below), whose sum is σ = 41117103360000. Its totient is φ = 10617349522080.

The previous prime is 21581301271247. The next prime is 21581301271297. The reversal of 21581301271256 is 65217210318512.

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, 37787960 + ... + 38354823.

It is an arithmetic number, because the mean of its divisors is an integer number (1284909480000).

Almost surely, 2^{21581301271256} is an apocalyptic number.

It is an amenable number.

21581301271256 is a deficient number, since it is larger than the sum of its proper divisors (19535802088744).

21581301271256 is a wasteful number, since it uses less digits than its factorization.

21581301271256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76143359 (or 76143355 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 44.

Adding to 21581301271256 its reverse (65217210318512), we get a palindrome (86798511589768).

The spelling of 21581301271256 in words is "twenty-one trillion, five hundred eighty-one billion, three hundred one million, two hundred seventy-one thousand, two hundred fifty-six".