161395021 has 4 divisors (see below), whose sum is σ = 166601344. Its totient is φ = 156188700.

The previous prime is 161395019. The next prime is 161395037. The reversal of 161395021 is 120593161.

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 161395021 - 2¹ = 161395019 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 (161395061) 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, 2603115 + ... + 2603176.

It is an arithmetic number, because the mean of its divisors is an integer number (41650336).

Almost surely, 2^161395021 is an apocalyptic number.

It is an amenable number.

161395021 is a deficient number, since it is larger than the sum of its proper divisors (5206323).

161395021 is an equidigital number, since it uses as much as digits as its factorization.

161395021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5206322.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 161395021 is about 12704.1340122025. The cubic root of 161395021 is about 544.4567389036.

The spelling of 161395021 in words is "one hundred sixty-one million, three hundred ninety-five thousand, twenty-one".