21971833 has 8 divisors (see below), whose sum is σ = 23872968. Its totient is φ = 20100864.

The previous prime is 21971827. The next prime is 21971849. The reversal of 21971833 is 33817912.

It can be written as a sum of positive squares in 4 ways, for example, as 1432809 + 20539024 = 1197^2 + 4532^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21971833 - 2⁵ = 21971801 is a prime.

It is a super-2 number, since 2×21971833² = 965522890759778, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21971333) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6010 + ... + 8947.

It is an arithmetic number, because the mean of its divisors is an integer number (2984121).

Almost surely, 2^21971833 is an apocalyptic number.

It is an amenable number.

21971833 is a deficient number, since it is larger than the sum of its proper divisors (1901135).

21971833 is a wasteful number, since it uses less digits than its factorization.

21971833 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15083.

The product of its digits is 9072, while the sum is 34.

The square root of 21971833 is about 4687.4121858441. The cubic root of 21971833 is about 280.0842985976.

The spelling of 21971833 in words is "twenty-one million, nine hundred seventy-one thousand, eight hundred thirty-three".