666402439 has 4 divisors (see below), whose sum is σ = 667920880. Its totient is φ = 664884000.

The previous prime is 666402419. The next prime is 666402461. The reversal of 666402439 is 934204666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 666402439 - 2⁹ = 666401927 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 (666402419) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 758562 + ... + 759439.

It is an arithmetic number, because the mean of its divisors is an integer number (166980220).

Almost surely, 2^666402439 is an apocalyptic number.

666402439 is a deficient number, since it is larger than the sum of its proper divisors (1518441).

666402439 is a wasteful number, since it uses less digits than its factorization.

666402439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1518440.

The product of its (nonzero) digits is 186624, while the sum is 40.

The square root of 666402439 is about 25814.7717208578. The cubic root of 666402439 is about 873.4650374215.

The spelling of 666402439 in words is "six hundred sixty-six million, four hundred two thousand, four hundred thirty-nine".