2551020021 has 32 divisors (see below), whose sum is σ = 4218762240. Its totient is φ = 1510110000.

The previous prime is 2551020007. The next prime is 2551020053. The reversal of 2551020021 is 1200201552.

It is not a de Polignac number, because 2551020021 - 2¹³ = 2551011829 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2551019976 and 2551020003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2551020421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 87105 + ... + 112646.

It is an arithmetic number, because the mean of its divisors is an integer number (131836320).

Almost surely, 2^2551020021 is an apocalyptic number.

It is an amenable number.

2551020021 is a deficient number, since it is larger than the sum of its proper divisors (1667742219).

2551020021 is a wasteful number, since it uses less digits than its factorization.

2551020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199814 (or 199808 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 2551020021 is about 50507.6233948896. The cubic root of 2551020021 is about 1366.3793471418.

Adding to 2551020021 its reverse (1200201552), we get a palindrome (3751221573).

The spelling of 2551020021 in words is "two billion, five hundred fifty-one million, twenty thousand, twenty-one".