21963213 has 12 divisors (see below), whose sum is σ = 31796128. Its totient is φ = 14609160.

The previous prime is 21963209. The next prime is 21963247. The reversal of 21963213 is 31236912.

21963213 is a `hidden beast` number, since 2 + 19 + 632 + 13 = 666.

It is not a de Polignac number, because 21963213 - 2² = 21963209 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21963313) 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, 1878 + ... + 6888.

Almost surely, 2^21963213 is an apocalyptic number.

It is an amenable number.

21963213 is a deficient number, since it is larger than the sum of its proper divisors (9832915).

21963213 is a wasteful number, since it uses less digits than its factorization.

21963213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5504 (or 5501 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 21963213 is about 4686.4926117514. The cubic root of 21963213 is about 280.0476662047.

It can be divided in two parts, 2196321 and 3, that added together give a square (2196324 = 1482²).

The spelling of 21963213 in words is "twenty-one million, nine hundred sixty-three thousand, two hundred thirteen".