21520423023 has 16 divisors (see below), whose sum is σ = 31310355072. Its totient is φ = 13039380000.

The previous prime is 21520423009. The next prime is 21520423117. The reversal of 21520423023 is 32032402512.

It is not a de Polignac number, because 21520423023 - 2⁵ = 21520422991 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21520422984 and 21520423002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520423003) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53193 + ... + 214173.

It is an arithmetic number, because the mean of its divisors is an integer number (1956897192).

Almost surely, 2^21520423023 is an apocalyptic number.

21520423023 is a deficient number, since it is larger than the sum of its proper divisors (9789932049).

21520423023 is a wasteful number, since it uses less digits than its factorization.

21520423023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165046.

The product of its (nonzero) digits is 2880, while the sum is 24.

Adding to 21520423023 its reverse (32032402512), we get a palindrome (53552825535).

The spelling of 21520423023 in words is "twenty-one billion, five hundred twenty million, four hundred twenty-three thousand, twenty-three".