20505750 has 64 divisors (see below), whose sum is σ = 53913600. Its totient is φ = 5176800.

The previous prime is 20505713. The next prime is 20505761. The reversal of 20505750 is 5750502.

It is a self number, because there is not a number n which added to its sum of digits gives 20505750.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13531 + ... + 14969.

It is an arithmetic number, because the mean of its divisors is an integer number (842400).

Almost surely, 2^20505750 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20505750, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26956800).

20505750 is an abundant number, since it is smaller than the sum of its proper divisors (33407850).

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

20505750 is a wasteful number, since it uses less digits than its factorization.

20505750 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1478 (or 1468 counting only the distinct ones).

The product of its (nonzero) digits is 1750, while the sum is 24.

The square root of 20505750 is about 4528.3275058238. The cubic root of 20505750 is about 273.7107698000.

The spelling of 20505750 in words is "twenty million, five hundred five thousand, seven hundred fifty".