21203896823 has 4 divisors (see below), whose sum is σ = 21205123320. Its totient is φ = 21202670328.

The previous prime is 21203896807. The next prime is 21203896829. The reversal of 21203896823 is 32869830212.

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 21203896823 - 2⁴ = 21203896807 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 (21203896829) 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, 586940 + ... + 622017.

It is an arithmetic number, because the mean of its divisors is an integer number (5301280830).

Almost surely, 2^21203896823 is an apocalyptic number.

21203896823 is a deficient number, since it is larger than the sum of its proper divisors (1226497).

21203896823 is a wasteful number, since it uses less digits than its factorization.

21203896823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1226496.

The product of its (nonzero) digits is 248832, while the sum is 44.

It can be divided in two parts, 2120389 and 6823, that added together give a palindrome (2127212).

The spelling of 21203896823 in words is "twenty-one billion, two hundred three million, eight hundred ninety-six thousand, eight hundred twenty-three".