21031133303021 has 4 divisors (see below), whose sum is σ = 22268258791452. Its totient is φ = 19794007814592.

The previous prime is 21031133303017. The next prime is 21031133303057. The reversal of 21031133303021 is 12030333113012.

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 10449612247396 + 10581521055625 = 3232586^2 + 3252925^2 .

It is a cyclic number.

It is not a de Polignac number, because 21031133303021 - 2² = 21031133303017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031133303321) 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, 618562744190 + ... + 618562744223.

It is an arithmetic number, because the mean of its divisors is an integer number (5567064697863).

Almost surely, 2^{21031133303021} is an apocalyptic number.

It is an amenable number.

21031133303021 is a deficient number, since it is larger than the sum of its proper divisors (1237125488431).

21031133303021 is a wasteful number, since it uses less digits than its factorization.

21031133303021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1237125488430.

The product of its (nonzero) digits is 972, while the sum is 23.

Adding to 21031133303021 its reverse (12030333113012), we get a palindrome (33061466416033).

The spelling of 21031133303021 in words is "twenty-one trillion, thirty-one billion, one hundred thirty-three million, three hundred three thousand, twenty-one".