21210222091 has 4 divisors (see below), whose sum is σ = 22457882232. Its totient is φ = 19962561952.

The previous prime is 21210222073. The next prime is 21210222113. The reversal of 21210222091 is 19022201212.

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

It is a cyclic number.

It is not a de Polignac number, because 21210222091 - 2²⁷ = 21076004363 is a prime.

It is a super-2 number, since 2×21210222091² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21210222001) 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, 623830045 + ... + 623830078.

It is an arithmetic number, because the mean of its divisors is an integer number (5614470558).

Almost surely, 2^21210222091 is an apocalyptic number.

21210222091 is a deficient number, since it is larger than the sum of its proper divisors (1247660141).

21210222091 is a wasteful number, since it uses less digits than its factorization.

21210222091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247660140.

The product of its (nonzero) digits is 288, while the sum is 22.

The spelling of 21210222091 in words is "twenty-one billion, two hundred ten million, two hundred twenty-two thousand, ninety-one".