66515251566 has 16 divisors (see below), whose sum is σ = 140032108800. Its totient is φ = 21004816248.

The previous prime is 66515251541. The next prime is 66515251567.

66515251566 is nontrivially palindromic in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66515251567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291733446 + ... + 291733673.

It is an arithmetic number, because the mean of its divisors is an integer number (8752006800).

Almost surely, 2^66515251566 is an apocalyptic number.

66515251566 is an abundant number, since it is smaller than the sum of its proper divisors (73516857234).

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

66515251566 is a wasteful number, since it uses less digits than its factorization.

66515251566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 583467143.

The product of its digits is 1620000, while the sum is 48.

Subtracting from 66515251566 its product of digits (1620000), we obtain a palindrome (66513631566).

The spelling of 66515251566 in words is "sixty-six billion, five hundred fifteen million, two hundred fifty-one thousand, five hundred sixty-six".