21001211201 has 4 divisors (see below), whose sum is σ = 21107816532. Its totient is φ = 20894605872.

The previous prime is 21001211111. The next prime is 21001211261. The reversal of 21001211201 is 10211210012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 20828262400 + 172948801 = 144320^2 + 13151^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001211201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001211261) 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, 53302370 + ... + 53302763.

It is an arithmetic number, because the mean of its divisors is an integer number (5276954133).

Almost surely, 2^21001211201 is an apocalyptic number.

It is an amenable number.

21001211201 is a deficient number, since it is larger than the sum of its proper divisors (106605331).

21001211201 is a wasteful number, since it uses less digits than its factorization.

21001211201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106605330.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21001211201 its reverse (10211210012), we get a palindrome (31212421213).

The spelling of 21001211201 in words is "twenty-one billion, one million, two hundred eleven thousand, two hundred one".