212001021991 has 8 divisors (see below), whose sum is σ = 231573041424. Its totient is φ = 192478869120.

The previous prime is 212001021983. The next prime is 212001022003. The reversal of 212001021991 is 199120100212.

212001021991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 212001021991 - 2³ = 212001021983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212001021931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12457746 + ... + 12474751.

It is an arithmetic number, because the mean of its divisors is an integer number (28946630178).

Almost surely, 2^212001021991 is an apocalyptic number.

212001021991 is a deficient number, since it is larger than the sum of its proper divisors (19572019433).

212001021991 is a wasteful number, since it uses less digits than its factorization.

212001021991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24933281.

The product of its (nonzero) digits is 648, while the sum is 28.

The spelling of 212001021991 in words is "two hundred twelve billion, one million, twenty-one thousand, nine hundred ninety-one".