21945066 has 32 divisors (see below), whose sum is σ = 51565248. Its totient is φ = 6138240.

The previous prime is 21945043. The next prime is 21945067. The reversal of 21945066 is 66054912.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21945067) 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, 11931 + ... + 13646.

It is an arithmetic number, because the mean of its divisors is an integer number (1611414).

Almost surely, 2^21945066 is an apocalyptic number.

21945066 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21945066 is an abundant number, since it is smaller than the sum of its proper divisors (29620182).

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

21945066 is a wasteful number, since it uses less digits than its factorization.

21945066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25606.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 21945066 is about 4684.5561155781. The cubic root of 21945066 is about 279.9705156028.

Adding to 21945066 its reverse (66054912), we get a palindrome (87999978).

It can be divided in two parts, 2194 and 5066, that added together give a triangular number (7260 = T₁₂₀).

The spelling of 21945066 in words is "twenty-one million, nine hundred forty-five thousand, sixty-six".