664320381 has 4 divisors (see below), whose sum is σ = 885760512. Its totient is φ = 442880252.

The previous prime is 664320361. The next prime is 664320403. The reversal of 664320381 is 183023466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 664320381 - 2⁹ = 664319869 is a prime.

It is a super-2 number, since 2×664320381² = 882643137223970322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664320301) 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, 110720061 + ... + 110720066.

It is an arithmetic number, because the mean of its divisors is an integer number (221440128).

Almost surely, 2^664320381 is an apocalyptic number.

It is an amenable number.

664320381 is a deficient number, since it is larger than the sum of its proper divisors (221440131).

664320381 is a wasteful number, since it uses less digits than its factorization.

664320381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221440130.

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 664320381 is about 25774.4133007912. The cubic root of 664320381 is about 872.5544254410.

The spelling of 664320381 in words is "six hundred sixty-four million, three hundred twenty thousand, three hundred eighty-one".