20402559 has 24 divisors (see below), whose sum is σ = 30401280. Its totient is φ = 13178448.

The previous prime is 20402537. The next prime is 20402563. The reversal of 20402559 is 95520402.

It is a de Polignac number, because none of the positive numbers 2^k-20402559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20402579) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 58624 + ... + 58970.

It is an arithmetic number, because the mean of its divisors is an integer number (1266720).

Almost surely, 2^20402559 is an apocalyptic number.

20402559 is a deficient number, since it is larger than the sum of its proper divisors (9998721).

20402559 is a wasteful number, since it uses less digits than its factorization.

With its successor (20402560) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (539).

20402559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539 (or 536 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 20402559 is about 4516.9191934326. The cubic root of 20402559 is about 273.2508662908.

The spelling of 20402559 in words is "twenty million, four hundred two thousand, five hundred fifty-nine".