21473109 has 48 divisors (see below), whose sum is σ = 37065600. Its totient is φ = 11726208.

The previous prime is 21473107. The next prime is 21473147. The reversal of 21473109 is 90137412.

It is not a de Polignac number, because 21473109 - 2¹ = 21473107 is a prime.

It is a super-2 number, since 2×21473109² = 922188820251762, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21473107) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 196947 + ... + 197055.

It is an arithmetic number, because the mean of its divisors is an integer number (772200).

Almost surely, 2^21473109 is an apocalyptic number.

It is an amenable number.

21473109 is a deficient number, since it is larger than the sum of its proper divisors (15592491).

21473109 is a wasteful number, since it uses less digits than its factorization.

21473109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 231 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21473109 is about 4633.9086093707. The cubic root of 21473109 is about 277.9489106123.

The spelling of 21473109 in words is "twenty-one million, four hundred seventy-three thousand, one hundred nine".