161693491 has 2 divisors, whose sum is σ = 161693492. Its totient is φ = 161693490.

The previous prime is 161693429. The next prime is 161693537. The reversal of 161693491 is 194396161.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161693491 is a prime.

It is a super-2 number, since 2×161693491² = 52289570063534162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161697491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80846745 + 80846746.

It is an arithmetic number, because the mean of its divisors is an integer number (80846746).

Almost surely, 2^161693491 is an apocalyptic number.

161693491 is a deficient number, since it is larger than the sum of its proper divisors (1).

161693491 is an equidigital number, since it uses as much as digits as its factorization.

161693491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34992, while the sum is 40.

The square root of 161693491 is about 12715.8755498786. The cubic root of 161693491 is about 544.7921559671.

The spelling of 161693491 in words is "one hundred sixty-one million, six hundred ninety-three thousand, four hundred ninety-one".