1251263989 has 2 divisors, whose sum is σ = 1251263990. Its totient is φ = 1251263988.

The previous prime is 1251263987. The next prime is 1251264017. The reversal of 1251263989 is 9893621521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1170803089 + 80460900 = 34217^2 + 8970^2 .

It is a cyclic number.

It is not a de Polignac number, because 1251263989 - 2¹ = 1251263987 is a prime.

Together with 1251263987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1251263987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 625631994 + 625631995.

It is an arithmetic number, because the mean of its divisors is an integer number (625631995).

Almost surely, 2^1251263989 is an apocalyptic number.

It is an amenable number.

1251263989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251263989 is an equidigital number, since it uses as much as digits as its factorization.

1251263989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 233280, while the sum is 46.

The square root of 1251263989 is about 35373.2100465875. The cubic root of 1251263989 is about 1077.5803135998.

The spelling of 1251263989 in words is "one billion, two hundred fifty-one million, two hundred sixty-three thousand, nine hundred eighty-nine".