21311011023 has 4 divisors (see below), whose sum is σ = 28414681368. Its totient is φ = 14207340680.

The previous prime is 21311011003. The next prime is 21311011069. The reversal of 21311011023 is 32011011312.

It is a happy number.

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 21311011023 - 2²² = 21306816719 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21311010993 and 21311011011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311011003) 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, 3551835168 + ... + 3551835173.

It is an arithmetic number, because the mean of its divisors is an integer number (7103670342).

Almost surely, 2^21311011023 is an apocalyptic number.

21311011023 is a deficient number, since it is larger than the sum of its proper divisors (7103670345).

21311011023 is an equidigital number, since it uses as much as digits as its factorization.

21311011023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7103670344.

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21311011023 its reverse (32011011312), we get a palindrome (53322022335).

The spelling of 21311011023 in words is "twenty-one billion, three hundred eleven million, eleven thousand, twenty-three".