212021011091 has 4 divisors (see below), whose sum is σ = 212023088784. Its totient is φ = 212018933400.

The previous prime is 212021011087. The next prime is 212021011099. The reversal of 212021011091 is 190110120212.

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 212021011091 - 2² = 212021011087 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212021011099) 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, 877415 + ... + 1092656.

It is an arithmetic number, because the mean of its divisors is an integer number (53005772196).

Almost surely, 2^212021011091 is an apocalyptic number.

212021011091 is a deficient number, since it is larger than the sum of its proper divisors (2077693).

212021011091 is a wasteful number, since it uses less digits than its factorization.

212021011091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2077692.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 212021011091 in words is "two hundred twelve billion, twenty-one million, eleven thousand, ninety-one".