1378772991 has 12 divisors (see below), whose sum is σ = 1993502368. Its totient is φ = 918285984.

The previous prime is 1378772987. The next prime is 1378773023. The reversal of 1378772991 is 1992778731.

It is not a de Polignac number, because 1378772991 - 2² = 1378772987 is a prime.

It is a super-2 number, since 2×1378772991² = 3802029921422172162, 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 (1378772911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 64855 + ... + 83448.

Almost surely, 2^1378772991 is an apocalyptic number.

1378772991 is a deficient number, since it is larger than the sum of its proper divisors (614729377).

1378772991 is a wasteful number, since it uses less digits than its factorization.

1378772991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149342 (or 149339 counting only the distinct ones).

The product of its digits is 1333584, while the sum is 54.

The square root of 1378772991 is about 37131.8325833778. The cubic root of 1378772991 is about 1113.0062141990.

The spelling of 1378772991 in words is "one billion, three hundred seventy-eight million, seven hundred seventy-two thousand, nine hundred ninety-one".