6921997 has 4 divisors (see below), whose sum is σ = 7109116. Its totient is φ = 6734880.

The previous prime is 6921961. The next prime is 6922001. The reversal of 6921997 is 7991296.

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 2653641 + 4268356 = 1629^2 + 2066^2 .

It is a cyclic number.

It is not a de Polignac number, because 6921997 - 2⁷ = 6921869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6921917) 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, 93504 + ... + 93577.

It is an arithmetic number, because the mean of its divisors is an integer number (1777279).

Almost surely, 2^6921997 is an apocalyptic number.

It is an amenable number.

6921997 is a deficient number, since it is larger than the sum of its proper divisors (187119).

6921997 is a wasteful number, since it uses less digits than its factorization.

6921997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187118.

The product of its digits is 61236, while the sum is 43.

The square root of 6921997 is about 2630.9688329587. The cubic root of 6921997 is about 190.5799179246.

The spelling of 6921997 in words is "six million, nine hundred twenty-one thousand, nine hundred ninety-seven".