20861259 has 16 divisors (see below), whose sum is σ = 29500800. Its totient is φ = 13075776.

The previous prime is 20861257. The next prime is 20861263. The reversal of 20861259 is 95216802.

20861259 = T₂₄₀ + T₂₄₁ + ... + T₅₁₇.

It is not a de Polignac number, because 20861259 - 2¹ = 20861257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20861257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6607 + ... + 9239.

It is an arithmetic number, because the mean of its divisors is an integer number (1843800).

Almost surely, 2^20861259 is an apocalyptic number.

20861259 is a deficient number, since it is larger than the sum of its proper divisors (8639541).

20861259 is a wasteful number, since it uses less digits than its factorization.

20861259 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2794.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 20861259 is about 4567.4127249461. The cubic root of 20861259 is about 275.2834938754.

The spelling of 20861259 in words is "twenty million, eight hundred sixty-one thousand, two hundred fifty-nine".