21215043 has 12 divisors (see below), whose sum is σ = 31164120. Its totient is φ = 13903296.

The previous prime is 21215027. The next prime is 21215053. The reversal of 21215043 is 34051212.

It is not a de Polignac number, because 21215043 - 2⁴ = 21215027 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21215053) 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 11 ways as a sum of consecutive naturals, for example, 19446 + ... + 20507.

It is an arithmetic number, because the mean of its divisors is an integer number (2597010).

Almost surely, 2^21215043 is an apocalyptic number.

21215043 is a deficient number, since it is larger than the sum of its proper divisors (9949077).

21215043 is a wasteful number, since it uses less digits than its factorization.

21215043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40018 (or 40015 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21215043 is about 4605.9790490188. The cubic root of 21215043 is about 276.8309472552.

Adding to 21215043 its reverse (34051212), we get a palindrome (55266255).

The spelling of 21215043 in words is "twenty-one million, two hundred fifteen thousand, forty-three".