161562021 has 4 divisors (see below), whose sum is σ = 215416032. Its totient is φ = 107708012.

The previous prime is 161562013. The next prime is 161562047. The reversal of 161562021 is 120265161.

161562021 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 161562021 - 2³ = 161562013 is a prime.

It is a super-2 number, since 2×161562021² = 52204573259208882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161561982 and 161562000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161562061) 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, 26927001 + ... + 26927006.

It is an arithmetic number, because the mean of its divisors is an integer number (53854008).

Almost surely, 2^161562021 is an apocalyptic number.

It is an amenable number.

161562021 is a deficient number, since it is larger than the sum of its proper divisors (53854011).

161562021 is an equidigital number, since it uses as much as digits as its factorization.

161562021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53854010.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 161562021 is about 12710.7049765149. The cubic root of 161562021 is about 544.6444624410.

It can be divided in two parts, 1615 and 62021, that added together give a palindrome (63636).

The spelling of 161562021 in words is "one hundred sixty-one million, five hundred sixty-two thousand, twenty-one".