21511107712 has 16 divisors (see below), whose sum is σ = 42854160150. Its totient is φ = 10755553792.

The previous prime is 21511107691. The next prime is 21511107713. The reversal of 21511107712 is 21770111512.

It can be written as a sum of positive squares in only one way, i.e., 20034703936 + 1476403776 = 141544^2 + 38424^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is not an unprimeable number, because it can be changed into a prime (21511107713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84027637 + ... + 84027892.

Almost surely, 2^21511107712 is an apocalyptic number.

It is an amenable number.

21511107712 is a deficient number, since it is larger than the sum of its proper divisors (21343052438).

21511107712 is an equidigital number, since it uses as much as digits as its factorization.

21511107712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168055543 (or 168055531 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 28.

The spelling of 21511107712 in words is "twenty-one billion, five hundred eleven million, one hundred seven thousand, seven hundred twelve".