6991951 has 2 divisors, whose sum is σ = 6991952. Its totient is φ = 6991950.

The previous prime is 6991939. The next prime is 6991967. The reversal of 6991951 is 1591996.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6991951 - 2⁷ = 6991823 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6991991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3495975 + 3495976.

It is an arithmetic number, because the mean of its divisors is an integer number (3495976).

Almost surely, 2^6991951 is an apocalyptic number.

6991951 is a deficient number, since it is larger than the sum of its proper divisors (1).

6991951 is an equidigital number, since it uses as much as digits as its factorization.

6991951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21870, while the sum is 40.

The square root of 6991951 is about 2644.2297555243. The cubic root of 6991951 is about 191.2197702373.

The spelling of 6991951 in words is "six million, nine hundred ninety-one thousand, nine hundred fifty-one".