21213435 has 16 divisors (see below), whose sum is σ = 34408224. Its totient is φ = 11158272.

The previous prime is 21213431. The next prime is 21213449. The reversal of 21213435 is 53431212.

It is not a de Polignac number, because 21213435 - 2² = 21213431 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21213431) 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, 8592 + ... + 10781.

It is an arithmetic number, because the mean of its divisors is an integer number (2150514).

Almost surely, 2^21213435 is an apocalyptic number.

21213435 is a deficient number, since it is larger than the sum of its proper divisors (13194789).

21213435 is a wasteful number, since it uses less digits than its factorization.

21213435 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19454.

The product of its digits is 720, while the sum is 21.

The square root of 21213435 is about 4605.8044899887. The cubic root of 21213435 is about 276.8239529193.

Adding to 21213435 its reverse (53431212), we get a palindrome (74644647).

The spelling of 21213435 in words is "twenty-one million, two hundred thirteen thousand, four hundred thirty-five".