390640673 has 4 divisors (see below), whose sum is σ = 390860820. Its totient is φ = 390420528.

The previous prime is 390640633. The next prime is 390640693. The reversal of 390640673 is 376046093.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 376046093 = 89 ⋅4225237.

It can be written as a sum of positive squares in 2 ways, for example, as 257538304 + 133102369 = 16048^2 + 11537^2 .

It is a cyclic number.

It is not a de Polignac number, because 390640673 - 2⁸ = 390640417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (390640633) 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, 107390 + ... + 110967.

It is an arithmetic number, because the mean of its divisors is an integer number (97715205).

Almost surely, 2^390640673 is an apocalyptic number.

It is an amenable number.

390640673 is a deficient number, since it is larger than the sum of its proper divisors (220147).

390640673 is a wasteful number, since it uses less digits than its factorization.

390640673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220146.

The product of its (nonzero) digits is 81648, while the sum is 38.

The square root of 390640673 is about 19764.6318710974. The cubic root of 390640673 is about 731.0142110902.

The spelling of 390640673 in words is "three hundred ninety million, six hundred forty thousand, six hundred seventy-three".