21100213421 has 8 divisors (see below), whose sum is σ = 24145894080. Its totient is φ = 18062373888.

The previous prime is 21100213367. The next prime is 21100213427. The reversal of 21100213421 is 12431200112.

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

It is a cyclic number.

It is not a de Polignac number, because 21100213421 - 2¹⁸ = 21099951277 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21100213421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100213427) 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, 1954511 + ... + 1965276.

It is an arithmetic number, because the mean of its divisors is an integer number (3018236760).

Almost surely, 2^21100213421 is an apocalyptic number.

It is an amenable number.

21100213421 is a deficient number, since it is larger than the sum of its proper divisors (3045680659).

21100213421 is an equidigital number, since it uses as much as digits as its factorization.

21100213421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3920563.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21100213421 its reverse (12431200112), we get a palindrome (33531413533).

The spelling of 21100213421 in words is "twenty-one billion, one hundred million, two hundred thirteen thousand, four hundred twenty-one".