1391385664 has 56 divisors (see below), whose sum is σ = 2868335640. Its totient is φ = 668860416.

The previous prime is 1391385659. The next prime is 1391385673. The reversal of 1391385664 is 4665831931.

It can be written as a sum of positive squares in 4 ways, for example, as 1115560000 + 275825664 = 33400^2 + 16608^2 .

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 475534 + ... + 478450.

Almost surely, 2^1391385664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1391385664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1434167820).

1391385664 is an abundant number, since it is smaller than the sum of its proper divisors (1476949976).

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

1391385664 is a wasteful number, since it uses less digits than its factorization.

1391385664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3215 (or 3205 counting only the distinct ones).

The product of its digits is 466560, while the sum is 46.

The square root of 1391385664 is about 37301.2823372066. The cubic root of 1391385664 is about 1116.3897526570.

The spelling of 1391385664 in words is "one billion, three hundred ninety-one million, three hundred eighty-five thousand, six hundred sixty-four".