13721840 has 80 divisors (see below), whose sum is σ = 35997696. Its totient is φ = 4819200.

The previous prime is 13721837. The next prime is 13721849. The reversal of 13721840 is 4812731.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13721849) 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, 27029 + ... + 27531.

Almost surely, 2^13721840 is an apocalyptic number.

13721840 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 13721840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17998848).

13721840 is an abundant number, since it is smaller than the sum of its proper divisors (22275856).

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

13721840 is a wasteful number, since it uses less digits than its factorization.

13721840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 558 (or 552 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 13721840 is about 3704.3002038172. The cubic root of 13721840 is about 239.4073339466.

The spelling of 13721840 in words is "thirteen million, seven hundred twenty-one thousand, eight hundred forty".