1291978944 has 56 divisors (see below), whose sum is σ = 3798183920. Its totient is φ = 430659072.

The previous prime is 1291978943. The next prime is 1291978949. The reversal of 1291978944 is 4498791921.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (1291978943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 372109 + ... + 375564.

Almost surely, 2^1291978944 is an apocalyptic number.

It is an amenable number.

1291978944 is an abundant number, since it is smaller than the sum of its proper divisors (2506204976).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1291978944 is an equidigital number, since it uses as much as digits as its factorization.

1291978944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 747694 (or 747678 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 54.

The square root of 1291978944 is about 35944.1086132345. The cubic root of 1291978944 is about 1089.1436036141.

The spelling of 1291978944 in words is "one billion, two hundred ninety-one million, nine hundred seventy-eight thousand, nine hundred forty-four".