251512397 has 2 divisors, whose sum is σ = 251512398. Its totient is φ = 251512396.

The previous prime is 251512357. The next prime is 251512403. The reversal of 251512397 is 793215152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 247936516 + 3575881 = 15746^2 + 1891^2 .

It is a cyclic number.

It is not a de Polignac number, because 251512397 - 2¹⁰ = 251511373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251512357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125756198 + 125756199.

It is an arithmetic number, because the mean of its divisors is an integer number (125756199).

Almost surely, 2^251512397 is an apocalyptic number.

It is an amenable number.

251512397 is a deficient number, since it is larger than the sum of its proper divisors (1).

251512397 is an equidigital number, since it uses as much as digits as its factorization.

251512397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18900, while the sum is 35.

The square root of 251512397 is about 15859.1423790822. The cubic root of 251512397 is about 631.2283057342.

The spelling of 251512397 in words is "two hundred fifty-one million, five hundred twelve thousand, three hundred ninety-seven".