2551001221 has 2 divisors, whose sum is σ = 2551001222. Its totient is φ = 2551001220.

The previous prime is 2551001197. The next prime is 2551001261. The reversal of 2551001221 is 1221001552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1559381121 + 991620100 = 39489^2 + 31490^2 .

It is a cyclic number.

It is not a de Polignac number, because 2551001221 - 2⁹ = 2551000709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2551001261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1275500610 + 1275500611.

It is an arithmetic number, because the mean of its divisors is an integer number (1275500611).

Almost surely, 2^2551001221 is an apocalyptic number.

It is an amenable number.

2551001221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2551001221 is an equidigital number, since it uses as much as digits as its factorization.

2551001221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 2551001221 is about 50507.4372840278. The cubic root of 2551001221 is about 1366.3759905766.

Adding to 2551001221 its reverse (1221001552), we get a palindrome (3772002773).

The spelling of 2551001221 in words is "two billion, five hundred fifty-one million, one thousand, two hundred twenty-one".