6990521 has 4 divisors (see below), whose sum is σ = 7179492. Its totient is φ = 6801552.

The previous prime is 6990517. The next prime is 6990527. The reversal of 6990521 is 1250996.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6553600 + 436921 = 2560^2 + 661^2 .

It is a cyclic number.

It is not a de Polignac number, because 6990521 - 2² = 6990517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6990527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94430 + ... + 94503.

It is an arithmetic number, because the mean of its divisors is an integer number (1794873).

Almost surely, 2^6990521 is an apocalyptic number.

It is an amenable number.

6990521 is a deficient number, since it is larger than the sum of its proper divisors (188971).

6990521 is a wasteful number, since it uses less digits than its factorization.

6990521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188970.

The product of its (nonzero) digits is 4860, while the sum is 32.

The square root of 6990521 is about 2643.9593415936. The cubic root of 6990521 is about 191.2067332030.

The spelling of 6990521 in words is "six million, nine hundred ninety thousand, five hundred twenty-one".