161998413 has 4 divisors (see below), whose sum is σ = 215997888. Its totient is φ = 107998940.

The previous prime is 161998393. The next prime is 161998433. The reversal of 161998413 is 314899161.

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, and also an emirpimes, since its reverse is a distinct semiprime: 314899161 = 3 ⋅104966387.

It is an interprime number because it is at equal distance from previous prime (161998393) and next prime (161998433).

It is a cyclic number.

It is not a de Polignac number, because 161998413 - 2⁵ = 161998381 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161998433) 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, 26999733 + ... + 26999738.

It is an arithmetic number, because the mean of its divisors is an integer number (53999472).

Almost surely, 2^161998413 is an apocalyptic number.

It is an amenable number.

161998413 is a deficient number, since it is larger than the sum of its proper divisors (53999475).

161998413 is an equidigital number, since it uses as much as digits as its factorization.

161998413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53999474.

The product of its digits is 46656, while the sum is 42.

The square root of 161998413 is about 12727.8597179573. The cubic root of 161998413 is about 545.1343977387.

The spelling of 161998413 in words is "one hundred sixty-one million, nine hundred ninety-eight thousand, four hundred thirteen".