2121604433021 has 4 divisors (see below), whose sum is σ = 2121607358844. Its totient is φ = 2121601507200.

The previous prime is 2121604432999. The next prime is 2121604433033. The reversal of 2121604433021 is 1203344061212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 19861264900 + 2101743168121 = 140930^2 + 1449739^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121604433021 - 2⁶ = 2121604432957 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 (2121604433041) 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, 527411 + ... + 2126351.

It is an arithmetic number, because the mean of its divisors is an integer number (530401839711).

Almost surely, 2^{2121604433021} is an apocalyptic number.

It is an amenable number.

2121604433021 is a deficient number, since it is larger than the sum of its proper divisors (2925823).

2121604433021 is a wasteful number, since it uses less digits than its factorization.

2121604433021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2925822.

The product of its (nonzero) digits is 6912, while the sum is 29.

Adding to 2121604433021 its reverse (1203344061212), we get a palindrome (3324948494233).

The spelling of 2121604433021 in words is "two trillion, one hundred twenty-one billion, six hundred four million, four hundred thirty-three thousand, twenty-one".