21211018 has 8 divisors (see below), whose sum is σ = 31902948. Its totient is φ = 10576704.

The previous prime is 21211013. The next prime is 21211033. The reversal of 21211018 is 81011212.

It can be written as a sum of positive squares in 2 ways, for example, as 21187609 + 23409 = 4603^2 + 153^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21210992 and 21211010.

It is not an unprimeable number, because it can be changed into a prime (21211013) 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, 13471 + ... + 14962.

Almost surely, 2^21211018 is an apocalyptic number.

21211018 is a deficient number, since it is larger than the sum of its proper divisors (10691930).

21211018 is a wasteful number, since it uses less digits than its factorization.

21211018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28808.

The product of its (nonzero) digits is 32, while the sum is 16.

The square root of 21211018 is about 4605.5420962141. The cubic root of 21211018 is about 276.8134390019.

The spelling of 21211018 in words is "twenty-one million, two hundred eleven thousand, eighteen".