21251536115 has 4 divisors (see below), whose sum is σ = 25501843344. Its totient is φ = 17001228888.

The previous prime is 21251536099. The next prime is 21251536129. The reversal of 21251536115 is 51163515212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21251536115 - 2⁴ = 21251536099 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2125153607 + ... + 2125153616.

It is an arithmetic number, because the mean of its divisors is an integer number (6375460836).

Almost surely, 2^21251536115 is an apocalyptic number.

21251536115 is a deficient number, since it is larger than the sum of its proper divisors (4250307229).

21251536115 is an equidigital number, since it uses as much as digits as its factorization.

21251536115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4250307228.

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

The spelling of 21251536115 in words is "twenty-one billion, two hundred fifty-one million, five hundred thirty-six thousand, one hundred fifteen".