251378993 has 2 divisors, whose sum is σ = 251378994. Its totient is φ = 251378992.

The previous prime is 251378929. The next prime is 251379013. The reversal of 251378993 is 399873152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 241087729 + 10291264 = 15527^2 + 3208^2 .

It is a cyclic number.

It is not a de Polignac number, because 251378993 - 2⁶ = 251378929 is a prime.

It is not a weakly prime, because it can be changed into another prime (251378923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125689496 + 125689497.

It is an arithmetic number, because the mean of its divisors is an integer number (125689497).

Almost surely, 2^251378993 is an apocalyptic number.

It is an amenable number.

251378993 is a deficient number, since it is larger than the sum of its proper divisors (1).

251378993 is an equidigital number, since it uses as much as digits as its factorization.

251378993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 408240, while the sum is 47.

The square root of 251378993 is about 15854.9359191389. The cubic root of 251378993 is about 631.1166833059.

The spelling of 251378993 in words is "two hundred fifty-one million, three hundred seventy-eight thousand, nine hundred ninety-three".