21962218 has 4 divisors (see below), whose sum is σ = 32943330. Its totient is φ = 10981108.

The previous prime is 21962209. The next prime is 21962261. The reversal of 21962218 is 81226912.

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

It can be written as a sum of positive squares in only one way, i.e., 15186609 + 6775609 = 3897^2 + 2603^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 21962218.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5490553 + ... + 5490556.

Almost surely, 2^21962218 is an apocalyptic number.

21962218 is a deficient number, since it is larger than the sum of its proper divisors (10981112).

21962218 is a wasteful number, since it uses less digits than its factorization.

21962218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10981111.

The product of its digits is 3456, while the sum is 31.

The square root of 21962218 is about 4686.3864544017. The cubic root of 21962218 is about 280.0434371387.

The spelling of 21962218 in words is "twenty-one million, nine hundred sixty-two thousand, two hundred eighteen".