999999657 has 24 divisors (see below), whose sum is σ = 1472826368. Its totient is φ = 653637600.

The previous prime is 999999613. The next prime is 999999667. The reversal of 999999657 is 756999999.

It is not a de Polignac number, because 999999657 - 2¹² = 999995561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999999607) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 178968 + ... + 184470.

Almost surely, 2^999999657 is an apocalyptic number.

It is an amenable number.

999999657 is a deficient number, since it is larger than the sum of its proper divisors (472826711).

999999657 is a wasteful number, since it uses less digits than its factorization.

999999657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5901 (or 5898 counting only the distinct ones).

The product of its digits is 111602610, while the sum is 72.

The square root of 999999657 is about 31622.7711783771. The cubic root of 999999657 is about 999.9998856667. Note that the first 3 decimals are identical.

The spelling of 999999657 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, six hundred fifty-seven".