21213363 has 4 divisors (see below), whose sum is σ = 28284488. Its totient is φ = 14142240.

The previous prime is 21213349. The next prime is 21213373. The reversal of 21213363 is 36331212.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21213363 - 2⁴ = 21213347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213343) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3535558 + ... + 3535563.

It is an arithmetic number, because the mean of its divisors is an integer number (7071122).

Almost surely, 2^21213363 is an apocalyptic number.

21213363 is a deficient number, since it is larger than the sum of its proper divisors (7071125).

21213363 is an equidigital number, since it uses as much as digits as its factorization.

21213363 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7071124.

The product of its digits is 648, while the sum is 21.

The square root of 21213363 is about 4605.7966737580. The cubic root of 21213363 is about 276.8236397318.

Adding to 21213363 its reverse (36331212), we get a palindrome (57544575).

The spelling of 21213363 in words is "twenty-one million, two hundred thirteen thousand, three hundred sixty-three".