21942305 has 16 divisors (see below), whose sum is σ = 32828544. Its totient is φ = 13678080.

The previous prime is 21942289. The next prime is 21942313. The reversal of 21942305 is 50324912.

It is not a de Polignac number, because 21942305 - 2⁴ = 21942289 is a prime.

It is a super-3 number, since 3×21942305³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28112 + ... + 28881.

It is an arithmetic number, because the mean of its divisors is an integer number (2051784).

Almost surely, 2^21942305 is an apocalyptic number.

It is an amenable number.

21942305 is a deficient number, since it is larger than the sum of its proper divisors (10886239).

21942305 is a wasteful number, since it uses less digits than its factorization.

21942305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57016.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 21942305 is about 4684.2614145669. The cubic root of 21942305 is about 279.9587736922.

It can be divided in two parts, 219 and 42305, that added together give a palindrome (42524).

The spelling of 21942305 in words is "twenty-one million, nine hundred forty-two thousand, three hundred five".