20781258 has 16 divisors (see below), whose sum is σ = 41610240. Its totient is φ = 6919136.

The previous prime is 20781251. The next prime is 20781263. The reversal of 20781258 is 85218702.

It is not an unprimeable number, because it can be changed into a prime (20781251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6391 + ... + 9077.

It is an arithmetic number, because the mean of its divisors is an integer number (2600640).

Almost surely, 2^20781258 is an apocalyptic number.

20781258 is an abundant number, since it is smaller than the sum of its proper divisors (20828982).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20781258 is a wasteful number, since it uses less digits than its factorization.

20781258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3981.

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 20781258 is about 4558.6465096561. The cubic root of 20781258 is about 274.9311475009.

The spelling of 20781258 in words is "twenty million, seven hundred eighty-one thousand, two hundred fifty-eight".