1378431631 has 4 divisors (see below), whose sum is σ = 1387683000. Its totient is φ = 1369180264.

The previous prime is 1378431623. The next prime is 1378431641. The reversal of 1378431631 is 1361348731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1361348731 = 97 ⋅14034523.

It is a cyclic number.

It is not a de Polignac number, because 1378431631 - 2³ = 1378431623 is a prime.

It is a super-2 number, since 2×1378431631² = 3800147522682640322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1378431601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4625461 + ... + 4625758.

It is an arithmetic number, because the mean of its divisors is an integer number (346920750).

Almost surely, 2^1378431631 is an apocalyptic number.

1378431631 is a deficient number, since it is larger than the sum of its proper divisors (9251369).

1378431631 is an equidigital number, since it uses as much as digits as its factorization.

1378431631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9251368.

The product of its digits is 36288, while the sum is 37.

The square root of 1378431631 is about 37127.2357037256. The cubic root of 1378431631 is about 1112.9143530144.

The spelling of 1378431631 in words is "one billion, three hundred seventy-eight million, four hundred thirty-one thousand, six hundred thirty-one".