21201011 has 16 divisors (see below), whose sum is σ = 23499168. Its totient is φ = 19008000.

The previous prime is 21200987. The next prime is 21201031. The reversal of 21201011 is 11010212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201011 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21201011.

It is not an unprimeable number, because it can be changed into a prime (21201031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87851 + ... + 88091.

It is an arithmetic number, because the mean of its divisors is an integer number (1468698).

Almost surely, 2^21201011 is an apocalyptic number.

21201011 is a deficient number, since it is larger than the sum of its proper divisors (2298157).

21201011 is a wasteful number, since it uses less digits than its factorization.

21201011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 21201011 is about 4604.4555595640. The cubic root of 21201011 is about 276.7699001860.

Adding to 21201011 its reverse (11010212), we get a palindrome (32211223).

The spelling of 21201011 in words is "twenty-one million, two hundred one thousand, eleven".