390909731 has 2 divisors, whose sum is σ = 390909732. Its totient is φ = 390909730.

The previous prime is 390909653. The next prime is 390909733. The reversal of 390909731 is 137909093.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-390909731 is a prime.

It is a super-2 number, since 2×390909731² = 305620835580984722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 390909733, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (390909733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195454865 + 195454866.

It is an arithmetic number, because the mean of its divisors is an integer number (195454866).

Almost surely, 2^390909731 is an apocalyptic number.

390909731 is a deficient number, since it is larger than the sum of its proper divisors (1).

390909731 is an equidigital number, since it uses as much as digits as its factorization.

390909731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45927, while the sum is 41.

The square root of 390909731 is about 19771.4372517528. The cubic root of 390909731 is about 731.1820038950.

The spelling of 390909731 in words is "three hundred ninety million, nine hundred nine thousand, seven hundred thirty-one".