501838991 has 2 divisors, whose sum is σ = 501838992. Its totient is φ = 501838990.

The previous prime is 501838957. The next prime is 501839027. The reversal of 501838991 is 199838105.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-501838991 is a 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 (501838901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 250919495 + 250919496.

It is an arithmetic number, because the mean of its divisors is an integer number (250919496).

Almost surely, 2^501838991 is an apocalyptic number.

501838991 is a deficient number, since it is larger than the sum of its proper divisors (1).

501838991 is an equidigital number, since it uses as much as digits as its factorization.

501838991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 44.

The square root of 501838991 is about 22401.7631225759. The cubic root of 501838991 is about 794.6724075179.

The spelling of 501838991 in words is "five hundred one million, eight hundred thirty-eight thousand, nine hundred ninety-one".