21971683 has 4 divisors (see below), whose sum is σ = 22043560. Its totient is φ = 21899808.

The previous prime is 21971681. The next prime is 21971687. The reversal of 21971683 is 38617912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21971683 - 2¹ = 21971681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21971681) 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 3 ways as a sum of consecutive naturals, for example, 35478 + ... + 36091.

It is an arithmetic number, because the mean of its divisors is an integer number (5510890).

Almost surely, 2^21971683 is an apocalyptic number.

21971683 is a deficient number, since it is larger than the sum of its proper divisors (71877).

21971683 is an equidigital number, since it uses as much as digits as its factorization.

21971683 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71876.

The product of its digits is 18144, while the sum is 37.

The square root of 21971683 is about 4687.3961855171. The cubic root of 21971683 is about 280.0836612249.

The spelling of 21971683 in words is "twenty-one million, nine hundred seventy-one thousand, six hundred eighty-three".