20542720 has 72 divisors (see below), whose sum is σ = 53716320. Its totient is φ = 7464960.

The previous prime is 20542673. The next prime is 20542729. The reversal of 20542720 is 2724502.

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 = 20542691 and 20542700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20542729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13351 + ... + 14809.

It is an arithmetic number, because the mean of its divisors is an integer number (746060).

Almost surely, 2^20542720 is an apocalyptic number.

20542720 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 20542720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26858160).

20542720 is an abundant number, since it is smaller than the sum of its proper divisors (33173600).

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

20542720 is a wasteful number, since it uses less digits than its factorization.

20542720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1491 (or 1477 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 22.

The square root of 20542720 is about 4532.4077486475. The cubic root of 20542720 is about 273.8751629089.

It can be divided in two parts, 2054 and 2720, that added together give a palindrome (4774).

The spelling of 20542720 in words is "twenty million, five hundred forty-two thousand, seven hundred twenty".