2551512221 has 8 divisors (see below), whose sum is σ = 2576749560. Its totient is φ = 2526308352.

The previous prime is 2551512203. The next prime is 2551512239. The reversal of 2551512221 is 1222151552.

It is a happy number.

2551512221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (2551512203) and next prime (2551512239).

It can be written as a sum of positive squares in 4 ways, for example, as 161671225 + 2389840996 = 12715^2 + 48886^2 .

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 2551512221 - 2¹⁸ = 2551250077 is a prime.

It is a super-2 number, since 2×2551512221² = 13020429227824705682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2551512281) 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, 161741 + ... + 176813.

It is an arithmetic number, because the mean of its divisors is an integer number (322093695).

Almost surely, 2^2551512221 is an apocalyptic number.

It is an amenable number.

2551512221 is a deficient number, since it is larger than the sum of its proper divisors (25237339).

2551512221 is a wasteful number, since it uses less digits than its factorization.

2551512221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16735.

The product of its digits is 2000, while the sum is 26.

The square root of 2551512221 is about 50512.4956916603. The cubic root of 2551512221 is about 1366.4672190075.

Adding to 2551512221 its reverse (1222151552), we get a palindrome (3773663773).

The spelling of 2551512221 in words is "two billion, five hundred fifty-one million, five hundred twelve thousand, two hundred twenty-one".