20259561 has 16 divisors (see below), whose sum is σ = 31039488. Its totient is φ = 11514000.

The previous prime is 20259559. The next prime is 20259571. The reversal of 20259561 is 16595202.

It is a happy number.

It is not a de Polignac number, because 20259561 - 2¹ = 20259559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20259521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1486 + ... + 6536.

It is an arithmetic number, because the mean of its divisors is an integer number (1939968).

Almost surely, 2^20259561 is an apocalyptic number.

20259561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20259561 is a deficient number, since it is larger than the sum of its proper divisors (10779927).

20259561 is a wasteful number, since it uses less digits than its factorization.

20259561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5252.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 20259561 is about 4501.0622079682. The cubic root of 20259561 is about 272.6109796814.

The spelling of 20259561 in words is "twenty million, two hundred fifty-nine thousand, five hundred sixty-one".