161662921 has 4 divisors (see below), whose sum is σ = 184757632. Its totient is φ = 138568212.

The previous prime is 161662913. The next prime is 161662927. The reversal of 161662921 is 129266161.

161662921 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.

It is a cyclic number.

It is not a de Polignac number, because 161662921 - 2³ = 161662913 is a prime.

It is a super-2 number, since 2×161662921² = 52269800052504482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161662927) 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, 11547345 + ... + 11547358.

It is an arithmetic number, because the mean of its divisors is an integer number (46189408).

Almost surely, 2^161662921 is an apocalyptic number.

It is an amenable number.

161662921 is a deficient number, since it is larger than the sum of its proper divisors (23094711).

161662921 is an equidigital number, since it uses as much as digits as its factorization.

161662921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23094710.

The product of its digits is 7776, while the sum is 34.

The square root of 161662921 is about 12714.6734523542. The cubic root of 161662921 is about 544.7578207448.

The spelling of 161662921 in words is "one hundred sixty-one million, six hundred sixty-two thousand, nine hundred twenty-one".