2121101021993 has 4 divisors (see below), whose sum is σ = 2121753069828. Its totient is φ = 2120448974160.

The previous prime is 2121101021989. The next prime is 2121101022109. The reversal of 2121101021993 is 3991201011212.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1101267644569 + 1019833377424 = 1049413^2 + 1009868^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121101021993 - 2² = 2121101021989 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121101021393) 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, 326019038 + ... + 326025543.

It is an arithmetic number, because the mean of its divisors is an integer number (530438267457).

Almost surely, 2^{2121101021993} is an apocalyptic number.

It is an amenable number.

2121101021993 is a deficient number, since it is larger than the sum of its proper divisors (652047835).

2121101021993 is an equidigital number, since it uses as much as digits as its factorization.

2121101021993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 652047834.

The product of its (nonzero) digits is 1944, while the sum is 32.

The spelling of 2121101021993 in words is "two trillion, one hundred twenty-one billion, one hundred one million, twenty-one thousand, nine hundred ninety-three".