2121010211981 has 4 divisors (see below), whose sum is σ = 2121053187264. Its totient is φ = 2120967236700.

The previous prime is 2121010211977. The next prime is 2121010211987. The reversal of 2121010211981 is 1891120101212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2121010211981 - 2² = 2121010211977 is a prime.

It is a super-2 number, since 2×2121010211981² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121010211987) 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, 21413525 + ... + 21512346.

It is an arithmetic number, because the mean of its divisors is an integer number (530263296816).

Almost surely, 2^{2121010211981} is an apocalyptic number.

It is an amenable number.

2121010211981 is a deficient number, since it is larger than the sum of its proper divisors (42975283).

2121010211981 is an equidigital number, since it uses as much as digits as its factorization.

2121010211981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42975282.

The product of its (nonzero) digits is 576, while the sum is 29.

The spelling of 2121010211981 in words is "two trillion, one hundred twenty-one billion, ten million, two hundred eleven thousand, nine hundred eighty-one".