1251287291 has 2 divisors, whose sum is σ = 1251287292. Its totient is φ = 1251287290.

The previous prime is 1251287287. The next prime is 1251287309. The reversal of 1251287291 is 1927821521.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1251287291 - 2² = 1251287287 is a prime.

It is not a weakly prime, because it can be changed into another prime (1251287221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 625643645 + 625643646.

It is an arithmetic number, because the mean of its divisors is an integer number (625643646).

Almost surely, 2^1251287291 is an apocalyptic number.

1251287291 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251287291 is an equidigital number, since it uses as much as digits as its factorization.

1251287291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 38.

The square root of 1251287291 is about 35373.5394186106. The cubic root of 1251287291 is about 1077.5870027346.

The spelling of 1251287291 in words is "one billion, two hundred fifty-one million, two hundred eighty-seven thousand, two hundred ninety-one".