161908813 has 4 divisors (see below), whose sum is σ = 176627808. Its totient is φ = 147189820.

The previous prime is 161908801. The next prime is 161908819. The reversal of 161908813 is 318809161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 161908813 - 2¹⁷ = 161777741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161908819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7359481 + ... + 7359502.

It is an arithmetic number, because the mean of its divisors is an integer number (44156952).

Almost surely, 2^161908813 is an apocalyptic number.

It is an amenable number.

161908813 is a deficient number, since it is larger than the sum of its proper divisors (14718995).

161908813 is a wasteful number, since it uses less digits than its factorization.

161908813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14718994.

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 161908813 is about 12724.3393934617. The cubic root of 161908813 is about 545.0338760751.

The spelling of 161908813 in words is "one hundred sixty-one million, nine hundred eight thousand, eight hundred thirteen".