1251138865 has 8 divisors (see below), whose sum is σ = 1501994880. Its totient is φ = 1000492272.

The previous prime is 1251138859. The next prime is 1251138871. The reversal of 1251138865 is 5688311521.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1251138859) and next prime (1251138871).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1251138865 - 2³ = 1251138857 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38895 + ... + 63364.

It is an arithmetic number, because the mean of its divisors is an integer number (187749360).

Almost surely, 2^1251138865 is an apocalyptic number.

It is an amenable number.

1251138865 is a deficient number, since it is larger than the sum of its proper divisors (250856015).

1251138865 is a wasteful number, since it uses less digits than its factorization.

1251138865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104711.

The product of its digits is 57600, while the sum is 40.

The square root of 1251138865 is about 35371.4413757766. The cubic root of 1251138865 is about 1077.5443937473.

The spelling of 1251138865 in words is "one billion, two hundred fifty-one million, one hundred thirty-eight thousand, eight hundred sixty-five".