21340020423 has 32 divisors (see below), whose sum is σ = 30945765312. Its totient is φ = 13027737600.

The previous prime is 21340020421. The next prime is 21340020437. The reversal of 21340020423 is 32402004312.

It is not a de Polignac number, because 21340020423 - 2¹ = 21340020421 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21340020423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340020421) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 766263 + ... + 793623.

It is an arithmetic number, because the mean of its divisors is an integer number (967055166).

Almost surely, 2^21340020423 is an apocalyptic number.

21340020423 is a deficient number, since it is larger than the sum of its proper divisors (9605744889).

21340020423 is a wasteful number, since it uses less digits than its factorization.

21340020423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27795.

The product of its (nonzero) digits is 1152, while the sum is 21.

Adding to 21340020423 its reverse (32402004312), we get a palindrome (53742024735).

The spelling of 21340020423 in words is "twenty-one billion, three hundred forty million, twenty thousand, four hundred twenty-three".