2565121621 has 8 divisors (see below), whose sum is σ = 2677158144. Its totient is φ = 2453127600.

The previous prime is 2565121609. The next prime is 2565121631. The reversal of 2565121621 is 1261215652.

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 2565121621 - 2⁵ = 2565121589 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 (2565121631) 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, 213835 + ... + 225511.

It is an arithmetic number, because the mean of its divisors is an integer number (334644768).

Almost surely, 2^2565121621 is an apocalyptic number.

It is an amenable number.

2565121621 is a deficient number, since it is larger than the sum of its proper divisors (112036523).

2565121621 is a wasteful number, since it uses less digits than its factorization.

2565121621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21251.

The product of its digits is 7200, while the sum is 31.

The square root of 2565121621 is about 50647.0297352174. The cubic root of 2565121621 is about 1368.8924255483.

The spelling of 2565121621 in words is "two billion, five hundred sixty-five million, one hundred twenty-one thousand, six hundred twenty-one".