13991280 has 80 divisors (see below), whose sum is σ = 43893024. Its totient is φ = 3686400.

The previous prime is 13991279. The next prime is 13991281. The reversal of 13991280 is 8219931.

It is an interprime number because it is at equal distance from previous prime (13991279) and next prime (13991281).

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

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13991281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22980 + ... + 23580.

Almost surely, 2^13991280 is an apocalyptic number.

13991280 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 13991280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21946512).

13991280 is an abundant number, since it is smaller than the sum of its proper divisors (29901744).

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

13991280 is a wasteful number, since it uses less digits than its factorization.

13991280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 714 (or 708 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 13991280 is about 3740.4919462552. The cubic root of 13991280 is about 240.9641768807.

It can be divided in two parts, 139 and 91280, that added together give a palindrome (91419).

The spelling of 13991280 in words is "thirteen million, nine hundred ninety-one thousand, two hundred eighty".