999657 has 12 divisors (see below), whose sum is σ = 1490944. Its totient is φ = 644760.

The previous prime is 999653. The next prime is 999667. The reversal of 999657 is 756999.

999657 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 999657 - 2² = 999653 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999653) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1513 + ... + 2070.

2⁹⁹⁹⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

999657 is a deficient number, since it is larger than the sum of its proper divisors (491287).

999657 is a wasteful number, since it uses less digits than its factorization.

999657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3620 (or 3617 counting only the distinct ones).

The product of its digits is 153090, while the sum is 45.

The square root of 999657 is about 999.8284852914. The cubic root of 999657 is about 99.9885653592.

The spelling of 999657 in words is "nine hundred ninety-nine thousand, six hundred fifty-seven".