54931991 has 2 divisors, whose sum is σ = 54931992. Its totient is φ = 54931990.

The previous prime is 54931937. The next prime is 54931997. The reversal of 54931991 is 19913945.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-54931991 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (54931997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27465995 + 27465996.

It is an arithmetic number, because the mean of its divisors is an integer number (27465996).

Almost surely, 2^54931991 is an apocalyptic number.

54931991 is a deficient number, since it is larger than the sum of its proper divisors (1).

54931991 is an equidigital number, since it uses as much as digits as its factorization.

54931991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43740, while the sum is 41.

The square root of 54931991 is about 7411.6119029534. The cubic root of 54931991 is about 380.1384329426.

The spelling of 54931991 in words is "fifty-four million, nine hundred thirty-one thousand, nine hundred ninety-one".