1688870391 has 16 divisors (see below), whose sum is σ = 2426801664. Its totient is φ = 1038551904.

The previous prime is 1688870371. The next prime is 1688870399. The reversal of 1688870391 is 1930788861.

It is not a de Polignac number, because 1688870391 - 2⁶ = 1688870327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1688870399) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41470 + ... + 71396.

It is an arithmetic number, because the mean of its divisors is an integer number (151675104).

Almost surely, 2^1688870391 is an apocalyptic number.

1688870391 is a deficient number, since it is larger than the sum of its proper divisors (737931273).

1688870391 is a wasteful number, since it uses less digits than its factorization.

1688870391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31390.

The product of its (nonzero) digits is 580608, while the sum is 51.

The square root of 1688870391 is about 41095.8682959735. The cubic root of 1688870391 is about 1190.8729773498.

The spelling of 1688870391 in words is "one billion, six hundred eighty-eight million, eight hundred seventy thousand, three hundred ninety-one".