20500720 has 40 divisors (see below), whose sum is σ = 48121920. Its totient is φ = 8121600.

The previous prime is 20500717. The next prime is 20500741. The reversal of 20500720 is 2700502.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 20500694 and 20500703.

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 7 ways as a sum of consecutive naturals, for example, 7545 + ... + 9895.

It is an arithmetic number, because the mean of its divisors is an integer number (1203048).

Almost surely, 2^20500720 is an apocalyptic number.

20500720 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 20500720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24060960).

20500720 is an abundant number, since it is smaller than the sum of its proper divisors (27621200).

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

20500720 is a wasteful number, since it uses less digits than its factorization.

20500720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2473 (or 2467 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 16.

The square root of 20500720 is about 4527.7720790694. The cubic root of 20500720 is about 273.6883878216.

The spelling of 20500720 in words is "twenty million, five hundred thousand, seven hundred twenty".