6897991 has 2 divisors, whose sum is σ = 6897992. Its totient is φ = 6897990.

The previous prime is 6897949. The next prime is 6898009. The reversal of 6897991 is 1997986.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6897991 - 2¹¹ = 6895943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6897901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3448995 + 3448996.

It is an arithmetic number, because the mean of its divisors is an integer number (3448996).

Almost surely, 2^6897991 is an apocalyptic number.

6897991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6897991 is an equidigital number, since it uses as much as digits as its factorization.

6897991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 49.

The square root of 6897991 is about 2626.4026728588. The cubic root of 6897991 is about 190.3593476370.

The spelling of 6897991 in words is "six million, eight hundred ninety-seven thousand, nine hundred ninety-one".