21011201213 has 4 divisors (see below), whose sum is σ = 21011930940. Its totient is φ = 21010471488.

The previous prime is 21011201209. The next prime is 21011201231. The reversal of 21011201213 is 31210211012.

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 11728456804 + 9282744409 = 108298^2 + 96347^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011201213 - 2² = 21011201209 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011200213) 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, 319820 + ... + 379877.

It is an arithmetic number, because the mean of its divisors is an integer number (5252982735).

Almost surely, 2^21011201213 is an apocalyptic number.

It is an amenable number.

21011201213 is a deficient number, since it is larger than the sum of its proper divisors (729727).

21011201213 is an equidigital number, since it uses as much as digits as its factorization.

21011201213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 729726.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21011201213 its reverse (31210211012), we get a palindrome (52221412225).

The spelling of 21011201213 in words is "twenty-one billion, eleven million, two hundred one thousand, two hundred thirteen".