2156380221 has 4 divisors (see below), whose sum is σ = 2875173632. Its totient is φ = 1437586812.

The previous prime is 2156380217. The next prime is 2156380229. The reversal of 2156380221 is 1220836512.

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 not a de Polignac number, because 2156380221 - 2² = 2156380217 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 (2156380229) 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, 359396701 + ... + 359396706.

It is an arithmetic number, because the mean of its divisors is an integer number (718793408).

Almost surely, 2^2156380221 is an apocalyptic number.

It is an amenable number.

2156380221 is a deficient number, since it is larger than the sum of its proper divisors (718793411).

2156380221 is an equidigital number, since it uses as much as digits as its factorization.

2156380221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718793410.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 2156380221 is about 46436.8412039406. The cubic root of 2156380221 is about 1291.9383197733.

The spelling of 2156380221 in words is "two billion, one hundred fifty-six million, three hundred eighty thousand, two hundred twenty-one".