1306239440 has 80 divisors (see below), whose sum is σ = 3330697536. Its totient is φ = 472473600.

The previous prime is 1306239419. The next prime is 1306239479. The reversal of 1306239440 is 449326031.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×1306239440² = 3412522949223027200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1306239397 and 1306239406.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 165995 + ... + 173685.

Almost surely, 2^1306239440 is an apocalyptic number.

1306239440 is a gapful number since it is divisible by the number (10) 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 1306239440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1665348768).

1306239440 is an abundant number, since it is smaller than the sum of its proper divisors (2024458096).

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

1306239440 is a wasteful number, since it uses less digits than its factorization.

1306239440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7908 (or 7902 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 1306239440 is about 36141.9346466124. The cubic root of 1306239440 is about 1093.1361689217.

The spelling of 1306239440 in words is "one billion, three hundred six million, two hundred thirty-nine thousand, four hundred forty".