21213519 has 8 divisors (see below), whose sum is σ = 29773440. Its totient is φ = 13397976.

The previous prime is 21213487. The next prime is 21213553. The reversal of 21213519 is 91531212.

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

It is not a de Polignac number, because 21213519 - 2⁵ = 21213487 is a prime.

It is a super-2 number, since 2×21213519² = 900026776726722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 186027 + ... + 186140.

It is an arithmetic number, because the mean of its divisors is an integer number (3721680).

Almost surely, 2^21213519 is an apocalyptic number.

21213519 is a deficient number, since it is larger than the sum of its proper divisors (8559921).

21213519 is a wasteful number, since it uses less digits than its factorization.

21213519 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372189.

The product of its digits is 540, while the sum is 24.

The square root of 21213519 is about 4605.8136089078. The cubic root of 21213519 is about 276.8243183038.

It can be divided in two parts, 212 and 13519, that added together give a palindrome (13731).

The spelling of 21213519 in words is "twenty-one million, two hundred thirteen thousand, five hundred nineteen".