21011111210 has 8 divisors (see below), whose sum is σ = 37820000196. Its totient is φ = 8404444480.

The previous prime is 21011111203. The next prime is 21011111237. The reversal of 21011111210 is 1211111012.

It can be written as a sum of positive squares in 2 ways, for example, as 19022753929 + 1988357281 = 137923^2 + 44591^2 .

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 = 21011111191 and 21011111200.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1050555551 + ... + 1050555570.

Almost surely, 2^21011111210 is an apocalyptic number.

21011111210 is a deficient number, since it is larger than the sum of its proper divisors (16808888986).

21011111210 is a wasteful number, since it uses less digits than its factorization.

21011111210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2101111128.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21011111210 its reverse (1211111012), we get a palindrome (22222222222).

The spelling of 21011111210 in words is "twenty-one billion, eleven million, one hundred eleven thousand, two hundred ten".