21866029 has 12 divisors (see below), whose sum is σ = 24038100. Its totient is φ = 19862528.

The previous prime is 21866027. The next prime is 21866041. The reversal of 21866029 is 92066812.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 1885129 + 19980900 = 1373^2 + 4470^2 .

It is not a de Polignac number, because 21866029 - 2¹ = 21866027 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21865985 and 21866003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21866021) 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 11 ways as a sum of consecutive naturals, for example, 7077 + ... + 9685.

It is an arithmetic number, because the mean of its divisors is an integer number (2003175).

Almost surely, 2^21866029 is an apocalyptic number.

21866029 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21866029 is a deficient number, since it is larger than the sum of its proper divisors (2172071).

21866029 is a wasteful number, since it uses less digits than its factorization.

21866029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2672 (or 2655 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 21866029 is about 4676.1125948805. The cubic root of 21866029 is about 279.6339988319.

The spelling of 21866029 in words is "twenty-one million, eight hundred sixty-six thousand, twenty-nine".