21902166 has 96 divisors (see below), whose sum is σ = 57028608. Its totient is φ = 5987520.

The previous prime is 21902143. The next prime is 21902173. The reversal of 21902166 is 66120912.

It is a super-3 number, since 3×21902166³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 172395 + ... + 172521.

It is an arithmetic number, because the mean of its divisors is an integer number (594048).

Almost surely, 2^21902166 is an apocalyptic number.

21902166 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21902166, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28514304).

21902166 is an abundant number, since it is smaller than the sum of its proper divisors (35126442).

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

21902166 is a wasteful number, since it uses less digits than its factorization.

21902166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 21902166 is about 4679.9749999332. The cubic root of 21902166 is about 279.7879602143.

It can be divided in two parts, 2190 and 2166, that added together give a square (4356 = 66²).

The spelling of 21902166 in words is "twenty-one million, nine hundred two thousand, one hundred sixty-six".