399792981 has 32 divisors (see below), whose sum is σ = 618928128. Its totient is φ = 224838720.

The previous prime is 399792971. The next prime is 399793033. The reversal of 399792981 is 189297993.

It is not a de Polignac number, because 399792981 - 2⁶ = 399792917 is a prime.

It is a super-2 number, since 2×399792981² = 319668855313732722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399792901) 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 in 31 ways as a sum of consecutive naturals, for example, 406216 + ... + 407198.

It is an arithmetic number, because the mean of its divisors is an integer number (19341504).

Almost surely, 2^399792981 is an apocalyptic number.

It is an amenable number.

399792981 is a deficient number, since it is larger than the sum of its proper divisors (219135147).

399792981 is a wasteful number, since it uses less digits than its factorization.

399792981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1281.

The product of its digits is 2204496, while the sum is 57.

The square root of 399792981 is about 19994.8238551881. The cubic root of 399792981 is about 736.6791670403.

The spelling of 399792981 in words is "three hundred ninety-nine million, seven hundred ninety-two thousand, nine hundred eighty-one".