21221011013 has 4 divisors (see below), whose sum is σ = 21511709868. Its totient is φ = 20930312160.

The previous prime is 21221010997. The next prime is 21221011069. The reversal of 21221011013 is 31011012212.

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 6959396929 + 14261614084 = 83423^2 + 119422^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221011013 - 2⁴ = 21221010997 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 (21221013013) 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, 145349318 + ... + 145349463.

It is an arithmetic number, because the mean of its divisors is an integer number (5377927467).

Almost surely, 2^21221011013 is an apocalyptic number.

It is an amenable number.

21221011013 is a deficient number, since it is larger than the sum of its proper divisors (290698855).

21221011013 is an equidigital number, since it uses as much as digits as its factorization.

21221011013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290698854.

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

Adding to 21221011013 its reverse (31011012212), we get a palindrome (52232023225).

The spelling of 21221011013 in words is "twenty-one billion, two hundred twenty-one million, eleven thousand, thirteen".