1309254640 has 40 divisors (see below), whose sum is σ = 3118269168. Its totient is φ = 510927360.

The previous prime is 1309254623. The next prime is 1309254649. The reversal of 1309254640 is 464529031.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 1309254596 and 1309254605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1309254649) 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, 196302 + ... + 202861.

Almost surely, 2^1309254640 is an apocalyptic number.

1309254640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1309254640 is an abundant number, since it is smaller than the sum of its proper divisors (1809014528).

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

1309254640 is a wasteful number, since it uses less digits than its factorization.

1309254640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399217 (or 399211 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 1309254640 is about 36183.6239202211. The cubic root of 1309254640 is about 1093.9766200788.

The spelling of 1309254640 in words is "one billion, three hundred nine million, two hundred fifty-four thousand, six hundred forty".