21251144152515 has 32 divisors (see below), whose sum is σ = 36552919864320. Its totient is φ = 10508964447744.

The previous prime is 21251144152507. The next prime is 21251144152529. The reversal of 21251144152515 is 51525144115212.

It is not a de Polignac number, because 21251144152515 - 2³ = 21251144152507 is a prime.

It is a super-2 number, since 2×21251144152515² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 793235734 + ... + 793262523.

It is an arithmetic number, because the mean of its divisors is an integer number (1142278745760).

Almost surely, 2^{21251144152515} is an apocalyptic number.

21251144152515 is a deficient number, since it is larger than the sum of its proper divisors (15301775711805).

21251144152515 is a wasteful number, since it uses less digits than its factorization.

21251144152515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1586498331.

The product of its digits is 80000, while the sum is 39.

Adding to 21251144152515 its reverse (51525144115212), we get a palindrome (72776288267727).

The spelling of 21251144152515 in words is "twenty-one trillion, two hundred fifty-one billion, one hundred forty-four million, one hundred fifty-two thousand, five hundred fifteen".