815661957051 has 16 divisors (see below), whose sum is σ = 1208402915200. Its totient is φ = 543767964264.

The previous prime is 815661957001. The next prime is 815661957059. The reversal of 815661957051 is 150759166518.

815661957051 is a `hidden beast` number, since 8 + 1 + 5 + 6 + 6 + 19 + 570 + 51 = 666.

It is not a de Polignac number, because 815661957051 - 2¹³ = 815661948859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (815661957059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3139560 + ... + 3389418.

It is an arithmetic number, because the mean of its divisors is an integer number (75525182200).

Almost surely, 2^815661957051 is an apocalyptic number.

815661957051 is a deficient number, since it is larger than the sum of its proper divisors (392740958149).

815661957051 is a wasteful number, since it uses less digits than its factorization.

815661957051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370775 (or 370769 counting only the distinct ones).

The product of its (nonzero) digits is 2268000, while the sum is 54.

The spelling of 815661957051 in words is "eight hundred fifteen billion, six hundred sixty-one million, nine hundred fifty-seven thousand, fifty-one".