20021869 has 16 divisors (see below), whose sum is σ = 24350976. Its totient is φ = 16070400.

The previous prime is 20021851. The next prime is 20021873. The reversal of 20021869 is 96812002.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20021869 - 2⁷ = 20021741 is a prime.

It is a super-2 number, since 2×20021869² = 801750476506322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36739 + ... + 37279.

It is an arithmetic number, because the mean of its divisors is an integer number (1521936).

Almost surely, 2^20021869 is an apocalyptic number.

It is an amenable number.

20021869 is a deficient number, since it is larger than the sum of its proper divisors (4329107).

20021869 is a wasteful number, since it uses less digits than its factorization.

20021869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 876.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 20021869 is about 4474.5803155156. The cubic root of 20021869 is about 271.5406616190.

The spelling of 20021869 in words is "twenty million, twenty-one thousand, eight hundred sixty-nine".