21251525011256 has 8 divisors (see below), whose sum is σ = 39846609396120. Its totient is φ = 10625762505624.

The previous prime is 21251525011217. The next prime is 21251525011261. The reversal of 21251525011256 is 65211052515212.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1328220313196 + ... + 1328220313211.

It is an arithmetic number, because the mean of its divisors is an integer number (4980826174515).

Almost surely, 2^{21251525011256} is an apocalyptic number.

It is an amenable number.

21251525011256 is a deficient number, since it is larger than the sum of its proper divisors (18595084384864).

21251525011256 is a wasteful number, since it uses less digits than its factorization.

21251525011256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2656440626413 (or 2656440626409 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 38.

Adding to 21251525011256 its reverse (65211052515212), we get a palindrome (86462577526468).

The spelling of 21251525011256 in words is "twenty-one trillion, two hundred fifty-one billion, five hundred twenty-five million, eleven thousand, two hundred fifty-six".