665637852645 has 48 divisors (see below), whose sum is σ = 1210515331584. Its totient is φ = 337922928000.

The previous prime is 665637852619. The next prime is 665637852647. The reversal of 665637852645 is 546258736566.

665637852645 is a `hidden beast` number, since 6 + 6 + 5 + 63 + 7 + 8 + 526 + 45 = 666.

It is not a de Polignac number, because 665637852645 - 2⁹ = 665637852133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665637852647) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3826051 + ... + 3996240.

It is an arithmetic number, because the mean of its divisors is an integer number (25219069408).

Almost surely, 2^665637852645 is an apocalyptic number.

It is an amenable number.

665637852645 is a deficient number, since it is larger than the sum of its proper divisors (544877478939).

665637852645 is a wasteful number, since it uses less digits than its factorization.

665637852645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7822394 (or 7822391 counting only the distinct ones).

The product of its digits is 217728000, while the sum is 63.

The spelling of 665637852645 in words is "six hundred sixty-five billion, six hundred thirty-seven million, eight hundred fifty-two thousand, six hundred forty-five".