2166416621 has 4 divisors (see below), whose sum is σ = 2260608672. Its totient is φ = 2072224572.

The previous prime is 2166416533. The next prime is 2166416627. The reversal of 2166416621 is 1266146612.

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 2166416621 - 2²⁶ = 2099307757 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166416627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47095991 + ... + 47096036.

It is an arithmetic number, because the mean of its divisors is an integer number (565152168).

Almost surely, 2^2166416621 is an apocalyptic number.

It is an amenable number.

2166416621 is a deficient number, since it is larger than the sum of its proper divisors (94192051).

2166416621 is an equidigital number, since it uses as much as digits as its factorization.

2166416621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94192050.

The product of its digits is 20736, while the sum is 35.

The square root of 2166416621 is about 46544.7808137497. The cubic root of 2166416621 is about 1293.9395662823.

The spelling of 2166416621 in words is "two billion, one hundred sixty-six million, four hundred sixteen thousand, six hundred twenty-one".