21646204134 has 16 divisors (see below), whose sum is σ = 43335326640. Its totient is φ = 7208248320.

The previous prime is 21646204133. The next prime is 21646204183. The reversal of 21646204134 is 43140264612.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21646204095 and 21646204104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21646204133) 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, 1781707 + ... + 1793814.

It is an arithmetic number, because the mean of its divisors is an integer number (2708457915).

Almost surely, 2^21646204134 is an apocalyptic number.

21646204134 is an abundant number, since it is smaller than the sum of its proper divisors (21689122506).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21646204134 is a wasteful number, since it uses less digits than its factorization.

21646204134 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3576535.

The product of its (nonzero) digits is 27648, while the sum is 33.

Adding to 21646204134 its reverse (43140264612), we get a palindrome (64786468746).

The spelling of 21646204134 in words is "twenty-one billion, six hundred forty-six million, two hundred four thousand, one hundred thirty-four".