2251221621 has 16 divisors (see below), whose sum is σ = 3298068480. Its totient is φ = 1354558320.

The previous prime is 2251221611. The next prime is 2251221629. The reversal of 2251221621 is 1261221522.

It is not a de Polignac number, because 2251221621 - 2⁵ = 2251221589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2251221591 and 2251221600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2251221629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 240805 + ... + 249978.

It is an arithmetic number, because the mean of its divisors is an integer number (206129280).

Almost surely, 2^2251221621 is an apocalyptic number.

It is an amenable number.

2251221621 is a deficient number, since it is larger than the sum of its proper divisors (1046846859).

2251221621 is a wasteful number, since it uses less digits than its factorization.

2251221621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 490936.

The product of its digits is 960, while the sum is 24.

The square root of 2251221621 is about 47447.0401711213. The cubic root of 2251221621 is about 1310.6078062509.

Subtracting from 2251221621 its reverse (1261221522), we obtain a palindrome (990000099).

The spelling of 2251221621 in words is "two billion, two hundred fifty-one million, two hundred twenty-one thousand, six hundred twenty-one".