21212634 has 16 divisors (see below), whose sum is σ = 44921088. Its totient is φ = 6654912.

The previous prime is 21212629. The next prime is 21212641. The reversal of 21212634 is 43621212.

It is a self number, because there is not a number n which added to its sum of digits gives 21212634.

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, 103882 + ... + 104085.

It is an arithmetic number, because the mean of its divisors is an integer number (2807568).

Almost surely, 2^21212634 is an apocalyptic number.

21212634 is an abundant number, since it is smaller than the sum of its proper divisors (23708454).

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

21212634 is a wasteful number, since it uses less digits than its factorization.

21212634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207989.

The product of its digits is 576, while the sum is 21.

The square root of 21212634 is about 4605.7175336749. The cubic root of 21212634 is about 276.8204686686.

Adding to 21212634 its reverse (43621212), we get a palindrome (64833846).

The spelling of 21212634 in words is "twenty-one million, two hundred twelve thousand, six hundred thirty-four".