20887290 has 24 divisors (see below), whose sum is σ = 54307188. Its totient is φ = 5569920.

The previous prime is 20887261. The next prime is 20887313. The reversal of 20887290 is 9278802.

It can be written as a sum of positive squares in 2 ways, for example, as 19740249 + 1147041 = 4443^2 + 1071^2 .

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 115951 + ... + 116130.

Almost surely, 2^20887290 is an apocalyptic number.

20887290 is an abundant number, since it is smaller than the sum of its proper divisors (33419898).

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

20887290 is a wasteful number, since it uses less digits than its factorization.

20887290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232094 (or 232091 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 20887290 is about 4570.2614804845. The cubic root of 20887290 is about 275.3979472763.

The spelling of 20887290 in words is "twenty million, eight hundred eighty-seven thousand, two hundred ninety".