20851078815 has 24 divisors (see below), whose sum is σ = 41304994848. Its totient is φ = 9531921600.

The previous prime is 20851078769. The next prime is 20851078849. The reversal of 20851078815 is 51887015802.

It is not a de Polignac number, because 20851078815 - 2⁶ = 20851078751 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33096636 + ... + 33097265.

It is an arithmetic number, because the mean of its divisors is an integer number (1721041452).

Almost surely, 2^20851078815 is an apocalyptic number.

20851078815 is a deficient number, since it is larger than the sum of its proper divisors (20453916033).

20851078815 is a wasteful number, since it uses less digits than its factorization.

20851078815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66193919 (or 66193916 counting only the distinct ones).

The product of its (nonzero) digits is 179200, while the sum is 45.

The spelling of 20851078815 in words is "twenty billion, eight hundred fifty-one million, seventy-eight thousand, eight hundred fifteen".