66139494976 has 189 divisors, whose sum is σ = 146462919291. Its totient is φ = 29626675200.

The previous prime is 66139494943. The next prime is 66139495001. The reversal of 66139494976 is 67949493166.

The square root of 66139494976 is 257176.

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

It can be written as a sum of positive squares in 4 ways, for example, as 6102734400 + 60036760576 = 78120^2 + 245024^2 .

It is a Harshad number since it is a multiple of its sum of digits (64).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1084253986 + ... + 1084254046.

Almost surely, 2^66139494976 is an apocalyptic number.

66139494976 is the 257176-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66139494976

66139494976 is an abundant number, since it is smaller than the sum of its proper divisors (80323424315).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66139494976 is an equidigital number, since it uses as much as digits as its factorization.

66139494976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230 (or 111 counting only the distinct ones).

The product of its digits is 52907904, while the sum is 64.

Multiplying 66139494976 by its sum of digits (64), we get a square (4232927678464 = 2057408²).

66139494976 divided by its sum of digits (64) gives a square (1033429609 = 32147²).

The spelling of 66139494976 in words is "sixty-six billion, one hundred thirty-nine million, four hundred ninety-four thousand, nine hundred seventy-six".