21971933 has 2 divisors, whose sum is σ = 21971934. Its totient is φ = 21971932.

The previous prime is 21971927. The next prime is 21971947. The reversal of 21971933 is 33917912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11035684 + 10936249 = 3322^2 + 3307^2 .

It is a cyclic number.

It is not a de Polignac number, because 21971933 - 2¹² = 21967837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21971893 and 21971902.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21971903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10985966 + 10985967.

It is an arithmetic number, because the mean of its divisors is an integer number (10985967).

Almost surely, 2^21971933 is an apocalyptic number.

It is an amenable number.

21971933 is a deficient number, since it is larger than the sum of its proper divisors (1).

21971933 is an equidigital number, since it uses as much as digits as its factorization.

21971933 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10206, while the sum is 35.

The square root of 21971933 is about 4687.4228526985. The cubic root of 21971933 is about 280.0847235111.

The spelling of 21971933 in words is "twenty-one million, nine hundred seventy-one thousand, nine hundred thirty-three".