390749881 has 2 divisors, whose sum is σ = 390749882. Its totient is φ = 390749880.

The previous prime is 390749851. The next prime is 390749899. The reversal of 390749881 is 188947093.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 385533225 + 5216656 = 19635^2 + 2284^2 .

It is a cyclic number.

It is not a de Polignac number, because 390749881 - 2⁷ = 390749753 is a prime.

It is a super-2 number, since 2×390749881² = 305370939003028322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (390749831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195374940 + 195374941.

It is an arithmetic number, because the mean of its divisors is an integer number (195374941).

Almost surely, 2^390749881 is an apocalyptic number.

It is an amenable number.

390749881 is a deficient number, since it is larger than the sum of its proper divisors (1).

390749881 is an equidigital number, since it uses as much as digits as its factorization.

390749881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 49.

The square root of 390749881 is about 19767.3943907638. The cubic root of 390749881 is about 731.0823258286.

The spelling of 390749881 in words is "three hundred ninety million, seven hundred forty-nine thousand, eight hundred eighty-one".