20281806 has 32 divisors (see below), whose sum is σ = 45235200. Its totient is φ = 6735960.

The previous prime is 20281801. The next prime is 20281819. The reversal of 20281806 is 60818202.

It is a super-2 number, since 2×20281806² = 822703309243272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a plaindrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 20281806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20281801) 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, 19971 + ... + 20961.

It is an arithmetic number, because the mean of its divisors is an integer number (1413600).

Almost surely, 2^20281806 is an apocalyptic number.

20281806 is an abundant number, since it is smaller than the sum of its proper divisors (24953394).

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

20281806 is a wasteful number, since it uses less digits than its factorization.

20281806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1381 (or 1375 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 20281806 is about 4503.5326134047. The cubic root of 20281806 is about 272.7107188134.

The spelling of 20281806 in words is "twenty million, two hundred eighty-one thousand, eight hundred six".