21004213091 has 8 divisors (see below), whose sum is σ = 21684718464. Its totient is φ = 20323892160.

The previous prime is 21004213079. The next prime is 21004213093. The reversal of 21004213091 is 19031240012.

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 21004213091 - 2³⁴ = 3824343907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21004213093) 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, 207575 + ... + 291711.

It is an arithmetic number, because the mean of its divisors is an integer number (2710589808).

Almost surely, 2^21004213091 is an apocalyptic number.

21004213091 is a deficient number, since it is larger than the sum of its proper divisors (680505373).

21004213091 is an equidigital number, since it uses as much as digits as its factorization.

21004213091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92221.

The product of its (nonzero) digits is 432, while the sum is 23.

The spelling of 21004213091 in words is "twenty-one billion, four million, two hundred thirteen thousand, ninety-one".