1391705988 has 24 divisors (see below), whose sum is σ = 3388502208. Its totient is φ = 443732256.

The previous prime is 1391705981. The next prime is 1391705999. The reversal of 1391705988 is 8895071931.

It is a super-2 number, since 2×1391705988² = 3873691114070112288, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1391705988.

It is not an unprimeable number, because it can be changed into a prime (1391705981) 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, 2520931 + ... + 2521482.

It is an arithmetic number, because the mean of its divisors is an integer number (141187592).

Almost surely, 2^1391705988 is an apocalyptic number.

It is an amenable number.

1391705988 is an abundant number, since it is smaller than the sum of its proper divisors (1996796220).

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

1391705988 is a wasteful number, since it uses less digits than its factorization.

1391705988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5042443 (or 5042441 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 51.

The square root of 1391705988 is about 37305.5758298944. The cubic root of 1391705988 is about 1116.4754176171.

The spelling of 1391705988 in words is "one billion, three hundred ninety-one million, seven hundred five thousand, nine hundred eighty-eight".