21213368634 has 96 divisors (see below), whose sum is σ = 46712526336. Its totient is φ = 6414059520.

The previous prime is 21213368633. The next prime is 21213368647. The reversal of 21213368634 is 43686331212.

It is a junction number, because it is equal to n+sod(n) for n = 21213368592 and 21213368601.

It is not an unprimeable number, because it can be changed into a prime (21213368633) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6511534 + ... + 6514790.

It is an arithmetic number, because the mean of its divisors is an integer number (486588816).

Almost surely, 2^21213368634 is an apocalyptic number.

21213368634 is an abundant number, since it is smaller than the sum of its proper divisors (25499157702).

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

21213368634 is a wasteful number, since it uses less digits than its factorization.

21213368634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3428 (or 3409 counting only the distinct ones).

The product of its digits is 124416, while the sum is 39.

Adding to 21213368634 its reverse (43686331212), we get a palindrome (64899699846).

The spelling of 21213368634 in words is "twenty-one billion, two hundred thirteen million, three hundred sixty-eight thousand, six hundred thirty-four".