1688631345 has 24 divisors (see below), whose sum is σ = 3006071016. Its totient is φ = 876261888.

The previous prime is 1688631331. The next prime is 1688631377. The reversal of 1688631345 is 5431368861.

1688631345 is a `hidden beast` number, since 1 + 6 + 8 + 8 + 631 + 3 + 4 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1085241249 + 603390096 = 32943^2 + 24564^2 .

It is not a de Polignac number, because 1688631345 - 2⁵ = 1688631313 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1688631345.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 505432 + ... + 508761.

It is an arithmetic number, because the mean of its divisors is an integer number (125252959).

Almost surely, 2^1688631345 is an apocalyptic number.

1688631345 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1688631345 is a deficient number, since it is larger than the sum of its proper divisors (1317439671).

1688631345 is a wasteful number, since it uses less digits than its factorization.

1688631345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1014241 (or 1014238 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 1688631345 is about 41092.9597984862. The cubic root of 1688631345 is about 1190.8167885396.

The spelling of 1688631345 in words is "one billion, six hundred eighty-eight million, six hundred thirty-one thousand, three hundred forty-five".