20287521 has 12 divisors (see below), whose sum is σ = 29579472. Its totient is φ = 13397976.

The previous prime is 20287493. The next prime is 20287549. The reversal of 20287521 is 12578202.

It is an interprime number because it is at equal distance from previous prime (20287493) and next prime (20287549).

It is not a de Polignac number, because 20287521 - 2⁵ = 20287489 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20287591) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9571 + ... + 11496.

It is an arithmetic number, because the mean of its divisors is an integer number (2464956).

Almost surely, 2^20287521 is an apocalyptic number.

It is an amenable number.

20287521 is a deficient number, since it is larger than the sum of its proper divisors (9291951).

20287521 is a wasteful number, since it uses less digits than its factorization.

20287521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21180 (or 21177 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 20287521 is about 4504.1670706136. The cubic root of 20287521 is about 272.7363311840.

The spelling of 20287521 in words is "twenty million, two hundred eighty-seven thousand, five hundred twenty-one".