2551340221 has 4 divisors (see below), whose sum is σ = 2639317500. Its totient is φ = 2463362944.

The previous prime is 2551340213. The next prime is 2551340227. The reversal of 2551340221 is 1220431552.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1256348025 + 1294992196 = 35445^2 + 35986^2 .

It is a cyclic number.

It is not a de Polignac number, because 2551340221 - 2³ = 2551340213 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 (2551340227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43988596 + ... + 43988653.

It is an arithmetic number, because the mean of its divisors is an integer number (659829375).

Almost surely, 2^2551340221 is an apocalyptic number.

It is an amenable number.

2551340221 is a deficient number, since it is larger than the sum of its proper divisors (87977279).

2551340221 is an equidigital number, since it uses as much as digits as its factorization.

2551340221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87977278.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 2551340221 is about 50510.7931139474. The cubic root of 2551340221 is about 1366.4365133419.

Adding to 2551340221 its reverse (1220431552), we get a palindrome (3771771773).

The spelling of 2551340221 in words is "two billion, five hundred fifty-one million, three hundred forty thousand, two hundred twenty-one".