1261479187 has 4 divisors (see below), whose sum is σ = 1302172096. Its totient is φ = 1220786280.

The previous prime is 1261479181. The next prime is 1261479199. The reversal of 1261479187 is 7819741621.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1261479187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261479181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20346408 + ... + 20346469.

It is an arithmetic number, because the mean of its divisors is an integer number (325543024).

Almost surely, 2^1261479187 is an apocalyptic number.

1261479187 is a deficient number, since it is larger than the sum of its proper divisors (40692909).

1261479187 is an equidigital number, since it uses as much as digits as its factorization.

1261479187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40692908.

The product of its digits is 169344, while the sum is 46.

The square root of 1261479187 is about 35517.3082735728. The cubic root of 1261479187 is about 1080.5047900312.

It can be divided in two parts, 1261479 and 187, that added together give a triangular number (1261666 = T₁₅₈₈).

The spelling of 1261479187 in words is "one billion, two hundred sixty-one million, four hundred seventy-nine thousand, one hundred eighty-seven".