21100033021 has 4 divisors (see below), whose sum is σ = 22341211452. Its totient is φ = 19858854592.

The previous prime is 21100032977. The next prime is 21100033027. The reversal of 21100033021 is 12033000112.

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 11082825625 + 10017207396 = 105275^2 + 100086^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100033021 - 2⁹ = 21100032509 is a prime.

It is a super-2 number, since 2×21100033021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100032992 and 21100033010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100033027) 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, 620589190 + ... + 620589223.

It is an arithmetic number, because the mean of its divisors is an integer number (5585302863).

Almost surely, 2^21100033021 is an apocalyptic number.

It is an amenable number.

21100033021 is a deficient number, since it is larger than the sum of its proper divisors (1241178431).

21100033021 is a wasteful number, since it uses less digits than its factorization.

21100033021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1241178430.

The product of its (nonzero) digits is 36, while the sum is 13.

Adding to 21100033021 its reverse (12033000112), we get a palindrome (33133033133).

The spelling of 21100033021 in words is "twenty-one billion, one hundred million, thirty-three thousand, twenty-one".