21812502015 has 16 divisors (see below), whose sum is σ = 38777781600. Its totient is φ = 11633334336.

The previous prime is 21812502011. The next prime is 21812502043. The reversal of 21812502015 is 51020521812.

It is a happy number.

It is not a de Polignac number, because 21812502015 - 2² = 21812502011 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21812502015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21812502011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80786910 + ... + 80787179.

It is an arithmetic number, because the mean of its divisors is an integer number (2423611350).

Almost surely, 2^21812502015 is an apocalyptic number.

21812502015 is a deficient number, since it is larger than the sum of its proper divisors (16965279585).

21812502015 is a wasteful number, since it uses less digits than its factorization.

21812502015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161574103 (or 161574097 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 27.

The spelling of 21812502015 in words is "twenty-one billion, eight hundred twelve million, five hundred two thousand, fifteen".