66672760984921 has 81 divisors (see below), whose sum is σ = 85648114958679. Its totient is φ = 51726181433472.

The previous prime is 66672760984913. The next prime is 66672760984939. The reversal of 66672760984921 is 12948906727666.

The square root of 66672760984921 is 8165339.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 51155180721225 + 15517580263696 = 7152285^2 + 3939236^2 .

It is not a de Polignac number, because 66672760984921 - 2³ = 66672760984913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66672760994921) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 39381429151 + ... + 39381430843.

Almost surely, 2^{66672760984921} is an apocalyptic number.

66672760984921 is the 8165339-th square number.

66672760984921 is the 4082670-th centered octagonal number.

It is an amenable number.

66672760984921 is a deficient number, since it is larger than the sum of its proper divisors (18975353973758).

66672760984921 is an frugal number, since it uses more digits than its factorization.

66672760984921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3532 (or 1766 counting only the distinct ones).

The product of its (nonzero) digits is 658409472, while the sum is 73.

The spelling of 66672760984921 in words is "sixty-six trillion, six hundred seventy-two billion, seven hundred sixty million, nine hundred eighty-four thousand, nine hundred twenty-one".