2251511221 has 8 divisors (see below), whose sum is σ = 2260828800. Its totient is φ = 2242211280.

The previous prime is 2251511219. The next prime is 2251511233. The reversal of 2251511221 is 1221151522.

It is a happy number.

2251511221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 2251511221 - 2¹ = 2251511219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2251511192 and 2251511201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2251011221) 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, 290920 + ... + 298558.

It is an arithmetic number, because the mean of its divisors is an integer number (282603600).

Almost surely, 2^2251511221 is an apocalyptic number.

It is an amenable number.

2251511221 is a deficient number, since it is larger than the sum of its proper divisors (9317579).

2251511221 is an equidigital number, since it uses as much as digits as its factorization.

2251511221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8819.

The product of its digits is 400, while the sum is 22.

The square root of 2251511221 is about 47450.0918966444. The cubic root of 2251511221 is about 1310.6640032572.

Adding to 2251511221 its reverse (1221151522), we get a palindrome (3472662743).

The spelling of 2251511221 in words is "two billion, two hundred fifty-one million, five hundred eleven thousand, two hundred twenty-one".