21515523131012 has 24 divisors (see below), whose sum is σ = 38000088477120. Its totient is φ = 10658367931680.

The previous prime is 21515523131009. The next prime is 21515523131017. The reversal of 21515523131012 is 21013132551512.

It is a super-2 number, since 2×21515523131012² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21515523131012.

It is not an unprimeable number, because it can be changed into a prime (21515523131017) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 5074913 + ... + 8293719.

It is an arithmetic number, because the mean of its divisors is an integer number (1583337019880).

Almost surely, 2^{21515523131012} is an apocalyptic number.

It is an amenable number.

21515523131012 is a deficient number, since it is larger than the sum of its proper divisors (16484565346108).

21515523131012 is a wasteful number, since it uses less digits than its factorization.

21515523131012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3234251 (or 3234249 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 32.

Adding to 21515523131012 its reverse (21013132551512), we get a palindrome (42528655682524).

The spelling of 21515523131012 in words is "twenty-one trillion, five hundred fifteen billion, five hundred twenty-three million, one hundred thirty-one thousand, twelve".