21121010213 has 8 divisors (see below), whose sum is σ = 22065653880. Its totient is φ = 20190788800.

The previous prime is 21121010167. The next prime is 21121010221. The reversal of 21121010213 is 31201012112.

It can be written as a sum of positive squares in 4 ways, for example, as 13728105889 + 7392904324 = 117167^2 + 85982^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21121010213 - 2²⁰ = 21119961637 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 (21121010293) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3602570 + ... + 3608427.

It is an arithmetic number, because the mean of its divisors is an integer number (2758206735).

Almost surely, 2^21121010213 is an apocalyptic number.

It is an amenable number.

21121010213 is a deficient number, since it is larger than the sum of its proper divisors (944643667).

21121010213 is a wasteful number, since it uses less digits than its factorization.

21121010213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7211127.

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

Adding to 21121010213 its reverse (31201012112), we get a palindrome (52322022325).

The spelling of 21121010213 in words is "twenty-one billion, one hundred twenty-one million, ten thousand, two hundred thirteen".