390747981 has 16 divisors (see below), whose sum is σ = 567838656. Its totient is φ = 237561216.

The previous prime is 390747971. The next prime is 390748019. The reversal of 390747981 is 189747093.

It is not a de Polignac number, because 390747981 - 2¹¹ = 390745933 is a prime.

It is a super-2 number, since 2×390747981² = 305367969311152722, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 390747981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390747911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57120 + ... + 63593.

It is an arithmetic number, because the mean of its divisors is an integer number (35489916).

Almost surely, 2^390747981 is an apocalyptic number.

It is an amenable number.

390747981 is a deficient number, since it is larger than the sum of its proper divisors (177090675).

390747981 is a wasteful number, since it uses less digits than its factorization.

390747981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120812.

The product of its (nonzero) digits is 381024, while the sum is 48.

The square root of 390747981 is about 19767.3463317664. The cubic root of 390747981 is about 731.0811408774.

The spelling of 390747981 in words is "three hundred ninety million, seven hundred forty-seven thousand, nine hundred eighty-one".