21523044023 has 4 divisors (see below), whose sum is σ = 23178662808. Its totient is φ = 19867425240.

The previous prime is 21523043981. The next prime is 21523044031. The reversal of 21523044023 is 32044032512.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21523044023 - 2¹⁴ = 21523027639 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21523043983 and 21523044001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523044923) 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, 827809373 + ... + 827809398.

It is an arithmetic number, because the mean of its divisors is an integer number (5794665702).

Almost surely, 2^21523044023 is an apocalyptic number.

21523044023 is a deficient number, since it is larger than the sum of its proper divisors (1655618785).

21523044023 is a wasteful number, since it uses less digits than its factorization.

21523044023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1655618784.

The product of its (nonzero) digits is 5760, while the sum is 26.

Adding to 21523044023 its reverse (32044032512), we get a palindrome (53567076535).

The spelling of 21523044023 in words is "twenty-one billion, five hundred twenty-three million, forty-four thousand, twenty-three".