6999664 has 20 divisors (see below), whose sum is σ = 15499504. Its totient is φ = 2999808.

The previous prime is 6999661. The next prime is 6999673. The reversal of 6999664 is 4669996.

It is a happy number.

6999664 is digitally balanced in base 8, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×6999664² = 97990592225792, which contains 22 as substring.

6999664 is strictly pandigital in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6999661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31137 + ... + 31360.

Almost surely, 2^6999664 is an apocalyptic number.

It is an amenable number.

6999664 is an abundant number, since it is smaller than the sum of its proper divisors (8499840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6999664 is a wasteful number, since it uses less digits than its factorization.

6999664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62512 (or 62506 counting only the distinct ones).

The product of its digits is 629856, while the sum is 49.

The square root of 6999664 is about 2645.6878122711. The cubic root of 6999664 is about 191.2900575384.

It can be divided in two parts, 69996 and 64, that multiplied together give a palindrome (4479744).

The spelling of 6999664 in words is "six million, nine hundred ninety-nine thousand, six hundred sixty-four".