1209391272 has 48 divisors (see below), whose sum is σ = 3324335040. Its totient is φ = 397111968.

The previous prime is 1209391243. The next prime is 1209391277. The reversal of 1209391272 is 2721939021.

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 (1209391277) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120528 + ... + 130175.

It is an arithmetic number, because the mean of its divisors is an integer number (69256980).

Almost surely, 2^1209391272 is an apocalyptic number.

1209391272 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1209391272 is an abundant number, since it is smaller than the sum of its proper divisors (2114943768).

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

1209391272 is a wasteful number, since it uses less digits than its factorization.

1209391272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250782 (or 250775 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 1209391272 is about 34776.3033113067. The cubic root of 1209391272 is about 1065.4235120489.

The spelling of 1209391272 in words is "one billion, two hundred nine million, three hundred ninety-one thousand, two hundred seventy-two".