2121012100021 has 8 divisors (see below), whose sum is σ = 2123764083000. Its totient is φ = 2118260346048.

The previous prime is 2121012100001. The next prime is 2121012100027. The reversal of 2121012100021 is 1200012101212.

It can be written as a sum of positive squares in 4 ways, for example, as 1442975135121 + 678036964900 = 1201239^2 + 823430^2 .

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 2121012100021 - 2²³ = 2121003711413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121012099974 and 2121012100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121012100027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26226355 + ... + 26307103.

It is an arithmetic number, because the mean of its divisors is an integer number (265470510375).

Almost surely, 2^{2121012100021} is an apocalyptic number.

It is an amenable number.

2121012100021 is a deficient number, since it is larger than the sum of its proper divisors (2751982979).

2121012100021 is an equidigital number, since it uses as much as digits as its factorization.

2121012100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114503.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 2121012100021 its reverse (1200012101212), we get a palindrome (3321024201233).

The spelling of 2121012100021 in words is "two trillion, one hundred twenty-one billion, twelve million, one hundred thousand, twenty-one".