50815991 has 2 divisors, whose sum is σ = 50815992. Its totient is φ = 50815990.

The previous prime is 50815979. The next prime is 50815997. The reversal of 50815991 is 19951805.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-50815991 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (50815997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25407995 + 25407996.

It is an arithmetic number, because the mean of its divisors is an integer number (25407996).

Almost surely, 2^50815991 is an apocalyptic number.

50815991 is a deficient number, since it is larger than the sum of its proper divisors (1).

50815991 is an equidigital number, since it uses as much as digits as its factorization.

50815991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16200, while the sum is 38.

The square root of 50815991 is about 7128.5335799167. The cubic root of 50815991 is about 370.3964365424.

The spelling of 50815991 in words is "fifty million, eight hundred fifteen thousand, nine hundred ninety-one".