161884621 has 4 divisors (see below), whose sum is σ = 162160992. Its totient is φ = 161608252.

The previous prime is 161884589. The next prime is 161884643. The reversal of 161884621 is 126488161.

161884621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 126488161 = 67 ⋅1887883.

It is a cyclic number.

It is not a de Polignac number, because 161884621 - 2⁵ = 161884589 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 (161884651) 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, 137305 + ... + 138478.

It is an arithmetic number, because the mean of its divisors is an integer number (40540248).

Almost surely, 2^161884621 is an apocalyptic number.

It is an amenable number.

161884621 is a deficient number, since it is larger than the sum of its proper divisors (276371).

161884621 is an equidigital number, since it uses as much as digits as its factorization.

161884621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276370.

The product of its digits is 18432, while the sum is 37.

The square root of 161884621 is about 12723.3887388541. The cubic root of 161884621 is about 545.0067288679.

The spelling of 161884621 in words is "one hundred sixty-one million, eight hundred eighty-four thousand, six hundred twenty-one".