666156662440 has 64 divisors (see below), whose sum is σ = 1539588882960. Its totient is φ = 259222763520.

The previous prime is 666156662401. The next prime is 666156662441. The reversal of 666156662440 is 44266651666.

It can be written as a sum of positive squares in 8 ways, for example, as 316291510404 + 349865152036 = 562398^2 + 591494^2 .

It is not an unprimeable number, because it can be changed into a prime (666156662441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11326710 + ... + 11385370.

Almost surely, 2^666156662440 is an apocalyptic number.

It is an amenable number.

666156662440 is an abundant number, since it is smaller than the sum of its proper divisors (873432220520).

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

666156662440 is a wasteful number, since it uses less digits than its factorization.

666156662440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66382 (or 66378 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 52.

The spelling of 666156662440 in words is "six hundred sixty-six billion, one hundred fifty-six million, six hundred sixty-two thousand, four hundred forty".