991895507 has 2 divisors, whose sum is σ = 991895508. Its totient is φ = 991895506.

The previous prime is 991895483. The next prime is 991895543. The reversal of 991895507 is 705598199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991895507 - 2¹⁴ = 991879123 is a prime.

It is not a weakly prime, because it can be changed into another prime (991825507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495947753 + 495947754.

It is an arithmetic number, because the mean of its divisors is an integer number (495947754).

Almost surely, 2^991895507 is an apocalyptic number.

991895507 is a deficient number, since it is larger than the sum of its proper divisors (1).

991895507 is an equidigital number, since it uses as much as digits as its factorization.

991895507 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1020600, while the sum is 53.

The square root of 991895507 is about 31494.3726243277. The cubic root of 991895507 is about 997.2911712055.

The spelling of 991895507 in words is "nine hundred ninety-one million, eight hundred ninety-five thousand, five hundred seven".