21181434 has 16 divisors (see below), whose sum is σ = 42874272. Its totient is φ = 6975248.

The previous prime is 21181429. The next prime is 21181451. The reversal of 21181434 is 43418112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20769 + ... + 21764.

It is an arithmetic number, because the mean of its divisors is an integer number (2679642).

Almost surely, 2^21181434 is an apocalyptic number.

21181434 is an abundant number, since it is smaller than the sum of its proper divisors (21692838).

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

21181434 is a wasteful number, since it uses less digits than its factorization.

21181434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42621.

The product of its digits is 768, while the sum is 24.

The square root of 21181434 is about 4602.3291929196. The cubic root of 21181434 is about 276.6846842349.

Adding to 21181434 its reverse (43418112), we get a palindrome (64599546).

The spelling of 21181434 in words is "twenty-one million, one hundred eighty-one thousand, four hundred thirty-four".