21311221423 has 8 divisors (see below), whose sum is σ = 21443760000. Its totient is φ = 21178790688.

The previous prime is 21311221397. The next prime is 21311221441. The reversal of 21311221423 is 32412211312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21311221423 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21311221394 and 21311221403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311221453) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389353 + ... + 440701.

It is an arithmetic number, because the mean of its divisors is an integer number (2680470000).

Almost surely, 2^21311221423 is an apocalyptic number.

21311221423 is a deficient number, since it is larger than the sum of its proper divisors (132538577).

21311221423 is a wasteful number, since it uses less digits than its factorization.

21311221423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53921.

The product of its digits is 576, while the sum is 22.

Adding to 21311221423 its reverse (32412211312), we get a palindrome (53723432735).

The spelling of 21311221423 in words is "twenty-one billion, three hundred eleven million, two hundred twenty-one thousand, four hundred twenty-three".