666977401 has 2 divisors, whose sum is σ = 666977402. Its totient is φ = 666977400.

The previous prime is 666977347. The next prime is 666977407. The reversal of 666977401 is 104779666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 612513001 + 54464400 = 24749^2 + 7380^2 .

It is a cyclic number.

It is not a de Polignac number, because 666977401 - 2¹³ = 666969209 is a prime.

It is not a weakly prime, because it can be changed into another prime (666977407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333488700 + 333488701.

It is an arithmetic number, because the mean of its divisors is an integer number (333488701).

Almost surely, 2^666977401 is an apocalyptic number.

It is an amenable number.

666977401 is a deficient number, since it is larger than the sum of its proper divisors (1).

666977401 is an equidigital number, since it uses as much as digits as its factorization.

666977401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 381024, while the sum is 46.

The square root of 666977401 is about 25825.9056181966. The cubic root of 666977401 is about 873.7161693761.

The spelling of 666977401 in words is "six hundred sixty-six million, nine hundred seventy-seven thousand, four hundred one".