1397687931 has 6 divisors (see below), whose sum is σ = 2018882580. Its totient is φ = 931791948.

The previous prime is 1397687923. The next prime is 1397687939. The reversal of 1397687931 is 1397867931.

It is an interprime number because it is at equal distance from previous prime (1397687923) and next prime (1397687939).

It is not a de Polignac number, because 1397687931 - 2³ = 1397687923 is a prime.

It is a super-2 number, since 2×1397687931² = 3907063104926121522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1397687939) 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 5 ways as a sum of consecutive naturals, for example, 77649321 + ... + 77649338.

It is an arithmetic number, because the mean of its divisors is an integer number (336480430).

Almost surely, 2^1397687931 is an apocalyptic number.

1397687931 is a deficient number, since it is larger than the sum of its proper divisors (621194649).

1397687931 is a wasteful number, since it uses less digits than its factorization.

1397687931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155298665 (or 155298662 counting only the distinct ones).

The product of its digits is 1714608, while the sum is 54.

The square root of 1397687931 is about 37385.6647794312. The cubic root of 1397687931 is about 1118.0727727545.

The spelling of 1397687931 in words is "one billion, three hundred ninety-seven million, six hundred eighty-seven thousand, nine hundred thirty-one".