20528720 has 20 divisors (see below), whose sum is σ = 47729460. Its totient is φ = 8211456.

The previous prime is 20528713. The next prime is 20528737. The reversal of 20528720 is 2782502.

It can be written as a sum of positive squares in 2 ways, for example, as 14318656 + 6210064 = 3784^2 + 2492^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 20528720.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128225 + ... + 128384.

It is an arithmetic number, because the mean of its divisors is an integer number (2386473).

Almost surely, 2^20528720 is an apocalyptic number.

20528720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20528720 is an abundant number, since it is smaller than the sum of its proper divisors (27200740).

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

20528720 is a wasteful number, since it uses less digits than its factorization.

20528720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256622 (or 256616 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 26.

The square root of 20528720 is about 4530.8630524438. The cubic root of 20528720 is about 273.8129328564.

The spelling of 20528720 in words is "twenty million, five hundred twenty-eight thousand, seven hundred twenty".