2121020120021 has 24 divisors (see below), whose sum is σ = 2468735078040. Its totient is φ = 1814610068480.

The previous prime is 2121020119937. The next prime is 2121020120077. The reversal of 2121020120021 is 1200210201212.

It can be written as a sum of positive squares in 4 ways, for example, as 511067712100 + 1609952407921 = 714890^2 + 1268839^2 .

It is a de Polignac number, because none of the positive numbers 2^k-2121020120021 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2121020119978 and 2121020120005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121020123021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25813415 + ... + 25895451.

It is an arithmetic number, because the mean of its divisors is an integer number (102863961585).

Almost surely, 2^{2121020120021} is an apocalyptic number.

It is an amenable number.

2121020120021 is a deficient number, since it is larger than the sum of its proper divisors (347714958019).

2121020120021 is a wasteful number, since it uses less digits than its factorization.

2121020120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94645 (or 94634 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 2121020120021 its reverse (1200210201212), we get a palindrome (3321230321233).

The spelling of 2121020120021 in words is "two trillion, one hundred twenty-one billion, twenty million, one hundred twenty thousand, twenty-one".