21210434 has 24 divisors (see below), whose sum is σ = 37176768. Its totient is φ = 9075780.

The previous prime is 21210433. The next prime is 21210461. The reversal of 21210434 is 43401212.

It is not an unprimeable number, because it can be changed into a prime (21210433) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33299 + ... + 33929.

It is an arithmetic number, because the mean of its divisors is an integer number (1549032).

Almost surely, 2^21210434 is an apocalyptic number.

21210434 is a deficient number, since it is larger than the sum of its proper divisors (15966334).

21210434 is an frugal number, since it uses more digits than its factorization.

21210434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 668 (or 640 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21210434 is about 4605.4786939036. The cubic root of 21210434 is about 276.8108984900.

Adding to 21210434 its reverse (43401212), we get a palindrome (64611646).

The spelling of 21210434 in words is "twenty-one million, two hundred ten thousand, four hundred thirty-four".