21731283 has 12 divisors (see below), whose sum is σ = 35873968. Its totient is φ = 12417840.

The previous prime is 21731273. The next prime is 21731291. The reversal of 21731283 is 38213712.

It is not a de Polignac number, because 21731283 - 2²⁴ = 4954067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21731243) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 172408 + ... + 172533.

Almost surely, 2^21731283 is an apocalyptic number.

21731283 is a deficient number, since it is larger than the sum of its proper divisors (14142685).

21731283 is a wasteful number, since it uses less digits than its factorization.

21731283 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344954 (or 344951 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 21731283 is about 4661.6824216156. The cubic root of 21731283 is about 279.0584145619.

Adding to 21731283 its reverse (38213712), we get a palindrome (59944995).

The spelling of 21731283 in words is "twenty-one million, seven hundred thirty-one thousand, two hundred eighty-three".