20999250 has 160 divisors (see below), whose sum is σ = 63196848. Its totient is φ = 5184000.

The previous prime is 20999243. The next prime is 20999261. The reversal of 20999250 is 5299902.

It can be written as a sum of positive squares in 8 ways, for example, as 13689 + 20985561 = 117^2 + 4581^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 344220 + ... + 344280.

Almost surely, 2^20999250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20999250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31598424).

20999250 is an abundant number, since it is smaller than the sum of its proper divisors (42197598).

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

20999250 is a wasteful number, since it uses less digits than its factorization.

20999250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 20999250 is about 4582.4938625163. The cubic root of 20999250 is about 275.8891331655.

The spelling of 20999250 in words is "twenty million, nine hundred ninety-nine thousand, two hundred fifty".