161521499 has 2 divisors, whose sum is σ = 161521500. Its totient is φ = 161521498.

The previous prime is 161521447. The next prime is 161521511. The reversal of 161521499 is 994125161.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161521499 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (161521429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80760749 + 80760750.

It is an arithmetic number, because the mean of its divisors is an integer number (80760750).

Almost surely, 2^161521499 is an apocalyptic number.

161521499 is a deficient number, since it is larger than the sum of its proper divisors (1).

161521499 is an equidigital number, since it uses as much as digits as its factorization.

161521499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 38.

The square root of 161521499 is about 12709.1108658316. The cubic root of 161521499 is about 544.5989238336.

The spelling of 161521499 in words is "one hundred sixty-one million, five hundred twenty-one thousand, four hundred ninety-nine".