13639440 has 80 divisors (see below), whose sum is σ = 44782848. Its totient is φ = 3422208.

The previous prime is 13639433. The next prime is 13639453. The reversal of 13639440 is 4493631.

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

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 13639398 and 13639407.

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, 2409 + ... + 5751.

Almost surely, 2^13639440 is an apocalyptic number.

13639440 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 13639440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22391424).

13639440 is an abundant number, since it is smaller than the sum of its proper divisors (31143408).

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

13639440 is a wasteful number, since it uses less digits than its factorization.

13639440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3376 (or 3370 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 30.

The square root of 13639440 is about 3693.1612474952. The cubic root of 13639440 is about 238.9271557792.

The spelling of 13639440 in words is "thirteen million, six hundred thirty-nine thousand, four hundred forty".