166240621 has 4 divisors (see below), whose sum is σ = 166269244. Its totient is φ = 166212000.

The previous prime is 166240597. The next prime is 166240639. The reversal of 166240621 is 126042661.

166240621 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 an emirpimes, since its reverse is a distinct semiprime: 126042661 = 6379 ⋅19759.

It can be written as a sum of positive squares in 2 ways, for example, as 148718025 + 17522596 = 12195^2 + 4186^2 .

It is a cyclic number.

It is not a de Polignac number, because 166240621 - 2⁵ = 166240589 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166240621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166240681) 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, 2160 + ... + 18361.

It is an arithmetic number, because the mean of its divisors is an integer number (41567311).

Almost surely, 2^166240621 is an apocalyptic number.

It is an amenable number.

166240621 is a deficient number, since it is larger than the sum of its proper divisors (28623).

166240621 is an equidigital number, since it uses as much as digits as its factorization.

166240621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28622.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 166240621 is about 12893.4332510779. The cubic root of 166240621 is about 549.8518840827.

The spelling of 166240621 in words is "one hundred sixty-six million, two hundred forty thousand, six hundred twenty-one".