20902559 has 4 divisors (see below), whose sum is σ = 20911704. Its totient is φ = 20893416.

The previous prime is 20902529. The next prime is 20902573. The reversal of 20902559 is 95520902.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20902559 - 2⁸ = 20902303 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20902529) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2249 + ... + 6845.

It is an arithmetic number, because the mean of its divisors is an integer number (5227926).

Almost surely, 2^20902559 is an apocalyptic number.

20902559 is a deficient number, since it is larger than the sum of its proper divisors (9145).

20902559 is an equidigital number, since it uses as much as digits as its factorization.

20902559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9144.

The product of its (nonzero) digits is 8100, while the sum is 32.

The square root of 20902559 is about 4571.9316486579. The cubic root of 20902559 is about 275.4650379490.

The spelling of 20902559 in words is "twenty million, nine hundred two thousand, five hundred fifty-nine".