21117740615 has 4 divisors (see below), whose sum is σ = 25341288744. Its totient is φ = 16894192488.

The previous prime is 21117740599. The next prime is 21117740689. The reversal of 21117740615 is 51604771112.

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 21117740615 - 2⁴ = 21117740599 is a prime.

It is a Duffinian number.

It is a congruent 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, 2111774057 + ... + 2111774066.

It is an arithmetic number, because the mean of its divisors is an integer number (6335322186).

Almost surely, 2^21117740615 is an apocalyptic number.

21117740615 is a deficient number, since it is larger than the sum of its proper divisors (4223548129).

21117740615 is an equidigital number, since it uses as much as digits as its factorization.

21117740615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4223548128.

The product of its (nonzero) digits is 11760, while the sum is 35.

The spelling of 21117740615 in words is "twenty-one billion, one hundred seventeen million, seven hundred forty thousand, six hundred fifteen".