1261131972 has 12 divisors (see below), whose sum is σ = 2942641296. Its totient is φ = 420377320.

The previous prime is 1261131967. The next prime is 1261132039. The reversal of 1261131972 is 2791311621.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52547154 + ... + 52547177.

It is an arithmetic number, because the mean of its divisors is an integer number (245220108).

Almost surely, 2^1261131972 is an apocalyptic number.

1261131972 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1261131972 is an abundant number, since it is smaller than the sum of its proper divisors (1681509324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1261131972 is a wasteful number, since it uses less digits than its factorization.

1261131972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105094338 (or 105094336 counting only the distinct ones).

The product of its digits is 4536, while the sum is 33.

The square root of 1261131972 is about 35512.4199682308. The cubic root of 1261131972 is about 1080.4056466603.

The spelling of 1261131972 in words is "one billion, two hundred sixty-one million, one hundred thirty-one thousand, nine hundred seventy-two".