2551001981 has 12 divisors (see below), whose sum is σ = 2809049376. Its totient is φ = 2314911720.

The previous prime is 2551001969. The next prime is 2551002017. The reversal of 2551001981 is 1891001552.

2551001981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2551001981 - 2⁶ = 2551001917 is a prime.

It is a super-2 number, since 2×2551001981² = 13015222214131848722, 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 (2551001911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 49400 + ... + 86846.

It is an arithmetic number, because the mean of its divisors is an integer number (234087448).

Almost surely, 2^2551001981 is an apocalyptic number.

It is an amenable number.

2551001981 is a deficient number, since it is larger than the sum of its proper divisors (258047395).

2551001981 is a wasteful number, since it uses less digits than its factorization.

2551001981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38032 (or 38021 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 32.

The square root of 2551001981 is about 50507.4448076717. Note that the first 3 decimals coincide. The cubic root of 2551001981 is about 1366.3761262678.

The spelling of 2551001981 in words is "two billion, five hundred fifty-one million, one thousand, nine hundred eighty-one".