2551510021 has 2 divisors, whose sum is σ = 2551510022. Its totient is φ = 2551510020.

The previous prime is 2551509997. The next prime is 2551510043. The reversal of 2551510021 is 1200151552.

It is a happy number.

It is an a-pointer prime, because the next prime (2551510043) can be obtained adding 2551510021 to its sum of digits (22).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2466612225 + 84897796 = 49665^2 + 9214^2 .

It is a cyclic number.

It is not a de Polignac number, because 2551510021 - 2⁷ = 2551509893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2551509974 and 2551510001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2551510051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1275755010 + 1275755011.

It is an arithmetic number, because the mean of its divisors is an integer number (1275755011).

Almost surely, 2^2551510021 is an apocalyptic number.

It is an amenable number.

2551510021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2551510021 is an equidigital number, since it uses as much as digits as its factorization.

2551510021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 500, while the sum is 22.

The square root of 2551510021 is about 50512.4739148658. The cubic root of 2551510021 is about 1366.4668262693.

Adding to 2551510021 its reverse (1200151552), we get a palindrome (3751661573).

The spelling of 2551510021 in words is "two billion, five hundred fifty-one million, five hundred ten thousand, twenty-one".