666561051 has 24 divisors (see below), whose sum is σ = 1046405360. Its totient is φ = 406420416.

The previous prime is 666560989. The next prime is 666561061. The reversal of 666561051 is 150165666.

It is not a de Polignac number, because 666561051 - 2⁶ = 666560987 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 666560997 and 666561015.

It is not an unprimeable number, because it can be changed into a prime (666561061) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13381 + ... + 38886.

Almost surely, 2^666561051 is an apocalyptic number.

666561051 is a deficient number, since it is larger than the sum of its proper divisors (379844309).

666561051 is a wasteful number, since it uses less digits than its factorization.

666561051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52395 (or 52392 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 666561051 is about 25817.8436551157. The cubic root of 666561051 is about 873.5343304084.

The spelling of 666561051 in words is "six hundred sixty-six million, five hundred sixty-one thousand, fifty-one".