21261231261512 has 16 divisors (see below), whose sum is σ = 43488882126000. Its totient is φ = 9664196027920.

The previous prime is 21261231261511. The next prime is 21261231261539. The reversal of 21261231261512 is 21516213216212.

It is a super-2 number, since 2×21261231261512² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21261231261511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120802450262 + ... + 120802450437.

It is an arithmetic number, because the mean of its divisors is an integer number (2718055132875).

Almost surely, 2^{21261231261512} is an apocalyptic number.

21261231261512 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21261231261512 is an abundant number, since it is smaller than the sum of its proper divisors (22227650864488).

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

21261231261512 is a wasteful number, since it uses less digits than its factorization.

21261231261512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241604900716 (or 241604900712 counting only the distinct ones).

The product of its digits is 17280, while the sum is 35.

Adding to 21261231261512 its reverse (21516213216212), we get a palindrome (42777444477724).

The spelling of 21261231261512 in words is "twenty-one trillion, two hundred sixty-one billion, two hundred thirty-one million, two hundred sixty-one thousand, five hundred twelve".