21036834 has 80 divisors (see below), whose sum is σ = 58056768. Its totient is φ = 5544288.

The previous prime is 21036833. The next prime is 21036877. The reversal of 21036834 is 43863012.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 21036798 and 21036807.

It is not an unprimeable number, because it can be changed into a prime (21036833) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 14029 + ... + 15455.

Almost surely, 2^21036834 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21036834, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29028384).

21036834 is an abundant number, since it is smaller than the sum of its proper divisors (37019934).

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

21036834 is a wasteful number, since it uses less digits than its factorization.

21036834 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1461 (or 1452 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 21036834 is about 4586.5928530882. The cubic root of 21036834 is about 276.0536285204.

Adding to 21036834 its reverse (43863012), we get a palindrome (64899846).

The spelling of 21036834 in words is "twenty-one million, thirty-six thousand, eight hundred thirty-four".