1689978257 has 8 divisors (see below), whose sum is σ = 1844067072. Its totient is φ = 1535965200.

The previous prime is 1689978229. The next prime is 1689978271. The reversal of 1689978257 is 7528799861.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1689978257 - 2⁸ = 1689978001 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1689978257.

It is not an unprimeable number, because it can be changed into a prime (1689978557) 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, 34208 + ... + 67454.

It is an arithmetic number, because the mean of its divisors is an integer number (230508384).

Almost surely, 2^1689978257 is an apocalyptic number.

It is an amenable number.

1689978257 is a deficient number, since it is larger than the sum of its proper divisors (154088815).

1689978257 is a wasteful number, since it uses less digits than its factorization.

1689978257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37879.

The product of its digits is 15240960, while the sum is 62.

The square root of 1689978257 is about 41109.3451297877. The cubic root of 1689978257 is about 1191.1333169057.

The spelling of 1689978257 in words is "one billion, six hundred eighty-nine million, nine hundred seventy-eight thousand, two hundred fifty-seven".