666402397 has 16 divisors (see below), whose sum is σ = 747759600. Its totient is φ = 590786560.

The previous prime is 666402383. The next prime is 666402419. The reversal of 666402397 is 793204666.

It can be written as a sum of positive squares in 8 ways, for example, as 22714756 + 643687641 = 4766^2 + 25371^2 .

It is a cyclic number.

It is not a de Polignac number, because 666402397 - 2¹¹ = 666400349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666402307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3729 + ... + 36697.

It is an arithmetic number, because the mean of its divisors is an integer number (46734975).

Almost surely, 2^666402397 is an apocalyptic number.

It is an amenable number.

666402397 is a deficient number, since it is larger than the sum of its proper divisors (81357203).

666402397 is a wasteful number, since it uses less digits than its factorization.

666402397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33056.

The product of its (nonzero) digits is 326592, while the sum is 43.

The square root of 666402397 is about 25814.7709073701. The cubic root of 666402397 is about 873.4650190714.

The spelling of 666402397 in words is "six hundred sixty-six million, four hundred two thousand, three hundred ninety-seven".