21271731023 has 4 divisors (see below), whose sum is σ = 21350808360. Its totient is φ = 21192653688.

The previous prime is 21271731011. The next prime is 21271731053. The reversal of 21271731023 is 32013717212.

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 21271731023 - 2⁴ = 21271731007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21271731053) 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, 39538265 + ... + 39538802.

It is an arithmetic number, because the mean of its divisors is an integer number (5337702090).

Almost surely, 2^21271731023 is an apocalyptic number.

21271731023 is a deficient number, since it is larger than the sum of its proper divisors (79077337).

21271731023 is an equidigital number, since it uses as much as digits as its factorization.

21271731023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79077336.

The product of its (nonzero) digits is 3528, while the sum is 29.

The spelling of 21271731023 in words is "twenty-one billion, two hundred seventy-one million, seven hundred thirty-one thousand, twenty-three".