251898993 has 6 divisors (see below), whose sum is σ = 363854114. Its totient is φ = 167932656.

The previous prime is 251898989. The next prime is 251899001. The reversal of 251898993 is 399898152.

251898993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 251285904 + 613089 = 15852^2 + 783^2 .

It is not a de Polignac number, because 251898993 - 2² = 251898989 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251898943) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13994380 + ... + 13994397.

Almost surely, 2^251898993 is an apocalyptic number.

It is an amenable number.

251898993 is a deficient number, since it is larger than the sum of its proper divisors (111955121).

251898993 is a wasteful number, since it uses less digits than its factorization.

251898993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27988783 (or 27988780 counting only the distinct ones).

The product of its digits is 1399680, while the sum is 54.

The square root of 251898993 is about 15871.3261260677. The cubic root of 251898993 is about 631.5515574120.

The spelling of 251898993 in words is "two hundred fifty-one million, eight hundred ninety-eight thousand, nine hundred ninety-three".