21431421423 has 16 divisors (see below), whose sum is σ = 31757689440. Its totient is φ = 14284268352.

The previous prime is 21431421379. The next prime is 21431421439. The reversal of 21431421423 is 32412413412.

21431421423 is a `hidden beast` number, since 214 + 3 + 1 + 4 + 21 + 423 = 666.

It is not a de Polignac number, because 21431421423 - 2¹⁶ = 21431355887 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431421223) 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, 27315 + ... + 208827.

It is an arithmetic number, because the mean of its divisors is an integer number (1984855590).

Almost surely, 2^21431421423 is an apocalyptic number.

21431421423 is a deficient number, since it is larger than the sum of its proper divisors (10326268017).

21431421423 is a wasteful number, since it uses less digits than its factorization.

21431421423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185895 (or 185889 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

Adding to 21431421423 its reverse (32412413412), we get a palindrome (53843834835).

The spelling of 21431421423 in words is "twenty-one billion, four hundred thirty-one million, four hundred twenty-one thousand, four hundred twenty-three".