21694471 has 4 divisors (see below), whose sum is σ = 21753952. Its totient is φ = 21634992.

The previous prime is 21694441. The next prime is 21694481. The reversal of 21694471 is 17449612.

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 21694471 - 2¹³ = 21686279 is a prime.

It is a super-3 number, since 3×21694471³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21694441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29190 + ... + 29923.

It is an arithmetic number, because the mean of its divisors is an integer number (5438488).

Almost surely, 2^21694471 is an apocalyptic number.

21694471 is a deficient number, since it is larger than the sum of its proper divisors (59481).

21694471 is an equidigital number, since it uses as much as digits as its factorization.

21694471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59480.

The product of its digits is 12096, while the sum is 34.

The square root of 21694471 is about 4657.7323881906. The cubic root of 21694471 is about 278.9007539159.

The spelling of 21694471 in words is "twenty-one million, six hundred ninety-four thousand, four hundred seventy-one".