6990921 has 32 divisors (see below), whose sum is σ = 12103680. Its totient is φ = 3904848.

The previous prime is 6990913. The next prime is 6990923. The reversal of 6990921 is 1290996.

It is not a de Polignac number, because 6990921 - 2³ = 6990913 is a prime.

It is an Ulam number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6990923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8490 + ... + 9276.

It is an arithmetic number, because the mean of its divisors is an integer number (378240).

Almost surely, 2^6990921 is an apocalyptic number.

It is an amenable number.

6990921 is a deficient number, since it is larger than the sum of its proper divisors (5112759).

6990921 is a wasteful number, since it uses less digits than its factorization.

6990921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 850 (or 844 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 6990921 is about 2644.0349846400. The cubic root of 6990921 is about 191.2103801050.

The spelling of 6990921 in words is "six million, nine hundred ninety thousand, nine hundred twenty-one".