21236005471 has 4 divisors (see below), whose sum is σ = 21242991744. Its totient is φ = 21229019200.

The previous prime is 21236005459. The next prime is 21236005489. The reversal of 21236005471 is 17450063212.

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 21236005471 - 2²⁹ = 20699134559 is a prime.

It is a super-3 number, since 3×21236005471³ (a number of 32 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 (21236005411) 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, 3488575 + ... + 3494656.

It is an arithmetic number, because the mean of its divisors is an integer number (5310747936).

Almost surely, 2^21236005471 is an apocalyptic number.

21236005471 is a deficient number, since it is larger than the sum of its proper divisors (6986273).

21236005471 is an equidigital number, since it uses as much as digits as its factorization.

21236005471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6986272.

The product of its (nonzero) digits is 10080, while the sum is 31.

Adding to 21236005471 its reverse (17450063212), we get a palindrome (38686068683).

The spelling of 21236005471 in words is "twenty-one billion, two hundred thirty-six million, five thousand, four hundred seventy-one".