21313534 has 16 divisors (see below), whose sum is σ = 34949376. Its totient is φ = 9667800.

The previous prime is 21313531. The next prime is 21313541. The reversal of 21313534 is 43531312.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313531) 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, 16699 + ... + 17929.

It is an arithmetic number, because the mean of its divisors is an integer number (2184336).

Almost surely, 2^21313534 is an apocalyptic number.

21313534 is a deficient number, since it is larger than the sum of its proper divisors (13635842).

21313534 is a wasteful number, since it uses less digits than its factorization.

21313534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2031.

The product of its digits is 1080, while the sum is 22.

The square root of 21313534 is about 4616.6583152752. The cubic root of 21313534 is about 277.2586826142.

Adding to 21313534 its reverse (43531312), we get a palindrome (64844846).

It can be divided in two parts, 2131 and 3534, that added together give a palindrome (5665).

The spelling of 21313534 in words is "twenty-one million, three hundred thirteen thousand, five hundred thirty-four".