21215134 has 32 divisors (see below), whose sum is σ = 35020800. Its totient is φ = 9603360.

The previous prime is 21215111. The next prime is 21215137. The reversal of 21215134 is 43151212.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21215137) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110979 + ... + 111169.

It is an arithmetic number, because the mean of its divisors is an integer number (1094400).

Almost surely, 2^21215134 is an apocalyptic number.

21215134 is a deficient number, since it is larger than the sum of its proper divisors (13805666).

21215134 is a wasteful number, since it uses less digits than its factorization.

21215134 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328.

The product of its digits is 240, while the sum is 19.

The square root of 21215134 is about 4605.9889274726. The cubic root of 21215134 is about 276.8313430683.

Adding to 21215134 its reverse (43151212), we get a palindrome (64366346).

The spelling of 21215134 in words is "twenty-one million, two hundred fifteen thousand, one hundred thirty-four".