21969305 has 16 divisors (see below), whose sum is σ = 27291600. Its totient is φ = 16964352.

The previous prime is 21969293. The next prime is 21969313. The reversal of 21969305 is 50396912.

It can be written as a sum of positive squares in 8 ways, for example, as 104329 + 21864976 = 323^2 + 4676^2 .

It is not a de Polignac number, because 21969305 - 2⁴ = 21969289 is a prime.

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, 27167 + ... + 27963.

It is an arithmetic number, because the mean of its divisors is an integer number (1705725).

Almost surely, 2^21969305 is an apocalyptic number.

It is an amenable number.

21969305 is a deficient number, since it is larger than the sum of its proper divisors (5322295).

21969305 is a wasteful number, since it uses less digits than its factorization.

21969305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 988.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 21969305 is about 4687.1425197022. The cubic root of 21969305 is about 280.0735563552.

The spelling of 21969305 in words is "twenty-one million, nine hundred sixty-nine thousand, three hundred five".