999688642 has 16 divisors (see below), whose sum is σ = 1525309632. Its totient is φ = 491285520.

The previous prime is 999688633. The next prime is 999688643. The reversal of 999688642 is 246886999.

It is not an unprimeable number, because it can be changed into a prime (999688643) 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, 53683 + ... + 69865.

It is an arithmetic number, because the mean of its divisors is an integer number (95331852).

Almost surely, 2^999688642 is an apocalyptic number.

999688642 is a deficient number, since it is larger than the sum of its proper divisors (525620990).

999688642 is a wasteful number, since it uses less digits than its factorization.

999688642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16713.

The product of its digits is 13436928, while the sum is 61.

The square root of 999688642 is about 31617.8532161815. The cubic root of 999688642 is about 999.8962032266.

The spelling of 999688642 in words is "nine hundred ninety-nine million, six hundred eighty-eight thousand, six hundred forty-two".