166097621 has 4 divisors (see below), whose sum is σ = 166132032. Its totient is φ = 166063212.

The previous prime is 166097609. The next prime is 166097641. The reversal of 166097621 is 126790661.

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: 126790661 = 199 ⋅637139.

It is a cyclic number.

It is not a de Polignac number, because 166097621 - 2¹⁰ = 166096597 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 (166097641) 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, 8495 + ... + 20108.

It is an arithmetic number, because the mean of its divisors is an integer number (41533008).

Almost surely, 2^166097621 is an apocalyptic number.

It is an amenable number.

166097621 is a deficient number, since it is larger than the sum of its proper divisors (34411).

166097621 is an equidigital number, since it uses as much as digits as its factorization.

166097621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34410.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 166097621 is about 12887.8865994390. The cubic root of 166097621 is about 549.6941781918.

The spelling of 166097621 in words is "one hundred sixty-six million, ninety-seven thousand, six hundred twenty-one".