20281861 has 2 divisors, whose sum is σ = 20281862. Its totient is φ = 20281860.

The previous prime is 20281847. The next prime is 20281879. The reversal of 20281861 is 16818202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20079361 + 202500 = 4481^2 + 450^2 .

It is a cyclic number.

It is not a de Polignac number, because 20281861 - 2⁷ = 20281733 is a prime.

It is a super-2 number, since 2×20281861² = 822707771246642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20281801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10140930 + 10140931.

It is an arithmetic number, because the mean of its divisors is an integer number (10140931).

Almost surely, 2^20281861 is an apocalyptic number.

It is an amenable number.

20281861 is a deficient number, since it is larger than the sum of its proper divisors (1).

20281861 is an equidigital number, since it uses as much as digits as its factorization.

20281861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 20281861 is about 4503.5387197181. The cubic root of 20281861 is about 272.7109653246.

The spelling of 20281861 in words is "twenty million, two hundred eighty-one thousand, eight hundred sixty-one".