1261965312 has 104 divisors (see below), whose sum is σ = 3739027680. Its totient is φ = 420618240.

The previous prime is 1261965277. The next prime is 1261965317. The reversal of 1261965312 is 2135691621.

1261965312 is a `hidden beast` number, since 1 + 2 + 619 + 6 + 5 + 31 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (1261965317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104887 + ... + 116297.

Almost surely, 2^1261965312 is an apocalyptic number.

1261965312 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261965312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1869513840).

1261965312 is an abundant number, since it is smaller than the sum of its proper divisors (2477062368).

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

1261965312 is an equidigital number, since it uses as much as digits as its factorization.

1261965312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11444 (or 11416 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 1261965312 is about 35524.1511087879. The cubic root of 1261965312 is about 1080.6435670425.

The spelling of 1261965312 in words is "one billion, two hundred sixty-one million, nine hundred sixty-five thousand, three hundred twelve".