21072411256 has 64 divisors (see below), whose sum is σ = 42882840000. Its totient is φ = 9707338368.

The previous prime is 21072411253. The next prime is 21072411289. The reversal of 21072411256 is 65211427012.

It is a super-2 number, since 2×21072411256² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21072411253) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14745550 + ... + 14746978.

It is an arithmetic number, because the mean of its divisors is an integer number (670044375).

Almost surely, 2^21072411256 is an apocalyptic number.

21072411256 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21072411256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21441420000).

21072411256 is an abundant number, since it is smaller than the sum of its proper divisors (21810428744).

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

21072411256 is a wasteful number, since it uses less digits than its factorization.

21072411256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2313 (or 2283 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

Adding to 21072411256 its reverse (65211427012), we get a palindrome (86283838268).

The spelling of 21072411256 in words is "twenty-one billion, seventy-two million, four hundred eleven thousand, two hundred fifty-six".