212021022091 has 4 divisors (see below), whose sum is σ = 212028820552. Its totient is φ = 212013223632.

The previous prime is 212021022067. The next prime is 212021022113. The reversal of 212021022091 is 190220120212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212021022091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212021022001) 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, 3858306 + ... + 3912871.

It is an arithmetic number, because the mean of its divisors is an integer number (53007205138).

Almost surely, 2^212021022091 is an apocalyptic number.

212021022091 is a deficient number, since it is larger than the sum of its proper divisors (7798461).

212021022091 is an equidigital number, since it uses as much as digits as its factorization.

212021022091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7798460.

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

The spelling of 212021022091 in words is "two hundred twelve billion, twenty-one million, twenty-two thousand, ninety-one".