2155615621 has 8 divisors (see below), whose sum is σ = 2212231424. Its totient is φ = 2099686320.

The previous prime is 2155615603. The next prime is 2155615633. The reversal of 2155615621 is 1265165512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2155615621 - 2⁹ = 2155615109 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 (2155615421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165261 + ... + 177826.

It is an arithmetic number, because the mean of its divisors is an integer number (276528928).

Almost surely, 2^2155615621 is an apocalyptic number.

It is an amenable number.

2155615621 is a deficient number, since it is larger than the sum of its proper divisors (56615803).

2155615621 is a wasteful number, since it uses less digits than its factorization.

2155615621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343251.

The product of its digits is 18000, while the sum is 34.

The square root of 2155615621 is about 46428.6077865792. The cubic root of 2155615621 is about 1291.7856050828.

The spelling of 2155615621 in words is "two billion, one hundred fifty-five million, six hundred fifteen thousand, six hundred twenty-one".