2121221021999 has 4 divisors (see below), whose sum is σ = 2123044944936. Its totient is φ = 2119397099064.

The previous prime is 2121221021981. The next prime is 2121221022001. The reversal of 2121221021999 is 9991201221212.

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 2121221021999 - 2³² = 2116926054703 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 (2121221021299) 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, 911959724 + ... + 911962049.

It is an arithmetic number, because the mean of its divisors is an integer number (530761236234).

Almost surely, 2^{2121221021999} is an apocalyptic number.

2121221021999 is a deficient number, since it is larger than the sum of its proper divisors (1823922937).

2121221021999 is a wasteful number, since it uses less digits than its factorization.

2121221021999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1823922936.

The product of its (nonzero) digits is 23328, while the sum is 41.

The spelling of 2121221021999 in words is "two trillion, one hundred twenty-one billion, two hundred twenty-one million, twenty-one thousand, nine hundred ninety-nine".