21213235 has 8 divisors (see below), whose sum is σ = 25625376. Its totient is φ = 16857600.

The previous prime is 21213193. The next prime is 21213251. The reversal of 21213235 is 53231212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21213235 - 2¹³ = 21205043 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13294 + ... + 14803.

It is an arithmetic number, because the mean of its divisors is an integer number (3203172).

Almost surely, 2^21213235 is an apocalyptic number.

21213235 is a deficient number, since it is larger than the sum of its proper divisors (4412141).

21213235 is a wasteful number, since it uses less digits than its factorization.

21213235 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28253.

The product of its digits is 360, while the sum is 19.

The square root of 21213235 is about 4605.7827782039. The cubic root of 21213235 is about 276.8230829523.

Adding to 21213235 its reverse (53231212), we get a palindrome (74444447).

It can be divided in two parts, 2121 and 3235, that added together give a triangular number (5356 = T₁₀₃).

The spelling of 21213235 in words is "twenty-one million, two hundred thirteen thousand, two hundred thirty-five".