1261139115 has 32 divisors (see below), whose sum is σ = 2040192000. Its totient is φ = 665190144.

The previous prime is 1261139069. The next prime is 1261139119. The reversal of 1261139115 is 5119311621.

It is not a de Polignac number, because 1261139115 - 2⁸ = 1261138859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1261139119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 629886 + ... + 631884.

It is an arithmetic number, because the mean of its divisors is an integer number (63756000).

Almost surely, 2^1261139115 is an apocalyptic number.

1261139115 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1261139115 is a deficient number, since it is larger than the sum of its proper divisors (779052885).

1261139115 is a wasteful number, since it uses less digits than its factorization.

1261139115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2451.

The product of its digits is 1620, while the sum is 30.

The square root of 1261139115 is about 35512.5205385368. The cubic root of 1261139115 is about 1080.4076864476.

The spelling of 1261139115 in words is "one billion, two hundred sixty-one million, one hundred thirty-nine thousand, one hundred fifteen".