21110021213 has 4 divisors (see below), whose sum is σ = 21128173728. Its totient is φ = 21091868700.

The previous prime is 21110021173. The next prime is 21110021221. The reversal of 21110021213 is 31212001112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21110021213 - 2¹⁶ = 21109955677 is a prime.

It is a super-3 number, since 3×21110021213³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110021263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9074513 + ... + 9076838.

It is an arithmetic number, because the mean of its divisors is an integer number (5282043432).

Almost surely, 2^21110021213 is an apocalyptic number.

It is an amenable number.

21110021213 is a deficient number, since it is larger than the sum of its proper divisors (18152515).

21110021213 is a wasteful number, since it uses less digits than its factorization.

21110021213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18152514.

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

Adding to 21110021213 its reverse (31212001112), we get a palindrome (52322022325).

The spelling of 21110021213 in words is "twenty-one billion, one hundred ten million, twenty-one thousand, two hundred thirteen".