21037633121 has 4 divisors (see below), whose sum is σ = 21038030100. Its totient is φ = 21037236144.

The previous prime is 21037633103. The next prime is 21037633147. The reversal of 21037633121 is 12133673012.

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 10600967521 + 10436665600 = 102961^2 + 102160^2 .

It is a cyclic number.

It is not a de Polignac number, because 21037633121 - 2¹⁰ = 21037632097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21037636121) 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, 104006 + ... + 229983.

It is an arithmetic number, because the mean of its divisors is an integer number (5259507525).

Almost surely, 2^21037633121 is an apocalyptic number.

It is an amenable number.

21037633121 is a deficient number, since it is larger than the sum of its proper divisors (396979).

21037633121 is an equidigital number, since it uses as much as digits as its factorization.

21037633121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396978.

The product of its (nonzero) digits is 4536, while the sum is 29.

The spelling of 21037633121 in words is "twenty-one billion, thirty-seven million, six hundred thirty-three thousand, one hundred twenty-one".