20481720 has 128 divisors (see below), whose sum is σ = 72230400. Its totient is φ = 4548096.

The previous prime is 20481709. The next prime is 20481733. The reversal of 20481720 is 2718402.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30751 + ... + 31409.

It is an arithmetic number, because the mean of its divisors is an integer number (564300).

Almost surely, 2^20481720 is an apocalyptic number.

20481720 is a gapful number since it is divisible by the number (20) 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 20481720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36115200).

20481720 is an abundant number, since it is smaller than the sum of its proper divisors (51748680).

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

20481720 is a wasteful number, since it uses less digits than its factorization.

20481720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717 (or 713 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 20481720 is about 4525.6734305515. The cubic root of 20481720 is about 273.6038105211.

The spelling of 20481720 in words is "twenty million, four hundred eighty-one thousand, seven hundred twenty".