13721620 has 48 divisors (see below), whose sum is σ = 31808448. Its totient is φ = 4930560.

The previous prime is 13721599. The next prime is 13721621. The reversal of 13721620 is 2612731.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 13721591 and 13721600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13721621) 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, 21019 + ... + 21661.

It is an arithmetic number, because the mean of its divisors is an integer number (662676).

Almost surely, 2^13721620 is an apocalyptic number.

13721620 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 13721620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15904224).

13721620 is an abundant number, since it is smaller than the sum of its proper divisors (18086828).

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

13721620 is a wasteful number, since it uses less digits than its factorization.

13721620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 760 (or 758 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 13721620 is about 3704.2705084807. The cubic root of 13721620 is about 239.4060544804.

Subtracting from 13721620 its reverse (2612731), we obtain a square (11108889 = 3333²).

It can be divided in two parts, 13721 and 620, that added together give a palindrome (14341).

The spelling of 13721620 in words is "thirteen million, seven hundred twenty-one thousand, six hundred twenty".