21301211091 has 4 divisors (see below), whose sum is σ = 28401614792. Its totient is φ = 14200807392.

The previous prime is 21301210999. The next prime is 21301211093. The reversal of 21301211091 is 19011210312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21301211091 - 2¹⁵ = 21301178323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21301211093) 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, 3550201846 + ... + 3550201851.

It is an arithmetic number, because the mean of its divisors is an integer number (7100403698).

Almost surely, 2^21301211091 is an apocalyptic number.

21301211091 is a deficient number, since it is larger than the sum of its proper divisors (7100403701).

21301211091 is an equidigital number, since it uses as much as digits as its factorization.

21301211091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7100403700.

The product of its (nonzero) digits is 108, while the sum is 21.

The spelling of 21301211091 in words is "twenty-one billion, three hundred one million, two hundred eleven thousand, ninety-one".