390408661 has 4 divisors (see below), whose sum is σ = 390834400. Its totient is φ = 389982924.

The previous prime is 390408617. The next prime is 390408691. The reversal of 390408661 is 166804093.

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, and also an emirpimes, since its reverse is a distinct semiprime: 166804093 = 10301 ⋅16193.

It is a cyclic number.

It is not a de Polignac number, because 390408661 - 2⁷ = 390408533 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 390408661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390408611) 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, 211491 + ... + 213328.

It is an arithmetic number, because the mean of its divisors is an integer number (97708600).

Almost surely, 2^390408661 is an apocalyptic number.

It is an amenable number.

390408661 is a deficient number, since it is larger than the sum of its proper divisors (425739).

390408661 is an equidigital number, since it uses as much as digits as its factorization.

390408661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425738.

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 390408661 is about 19758.7616261749. The cubic root of 390408661 is about 730.8694594301.

The spelling of 390408661 in words is "three hundred ninety million, four hundred eight thousand, six hundred sixty-one".