665660220545638 has 8 divisors (see below), whose sum is σ = 998513713152288. Its totient is φ = 332822316161544.

The previous prime is 665660220545629. The next prime is 665660220545647. The reversal of 665660220545638 is 836545022066566.

It is an interprime number because it is at equal distance from previous prime (665660220545629) and next prime (665660220545647).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 665660220545638.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3896948881 + ... + 3897119692.

It is an arithmetic number, because the mean of its divisors is an integer number (124814214144036).

Almost surely, 2^{665660220545638} is an apocalyptic number.

665660220545638 is a deficient number, since it is larger than the sum of its proper divisors (332853492606650).

665660220545638 is a wasteful number, since it uses less digits than its factorization.

665660220545638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7794111278.

The product of its (nonzero) digits is 373248000, while the sum is 64.

The spelling of 665660220545638 in words is "six hundred sixty-five trillion, six hundred sixty billion, two hundred twenty million, five hundred forty-five thousand, six hundred thirty-eight".