21002121233 has 8 divisors (see below), whose sum is σ = 21838909800. Its totient is φ = 20172837888.

The previous prime is 21002121223. The next prime is 21002121247. The reversal of 21002121233 is 33212120012.

It can be written as a sum of positive squares in 4 ways, for example, as 2746598464 + 18255522769 = 52408^2 + 135113^2 .

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 21002121233 - 2¹² = 21002117137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002121223) 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, 1870598 + ... + 1881791.

It is an arithmetic number, because the mean of its divisors is an integer number (2729863725).

Almost surely, 2^21002121233 is an apocalyptic number.

It is an amenable number.

21002121233 is a deficient number, since it is larger than the sum of its proper divisors (836788567).

21002121233 is a wasteful number, since it uses less digits than its factorization.

21002121233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3752611.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21002121233 its reverse (33212120012), we get a palindrome (54214241245).

The spelling of 21002121233 in words is "twenty-one billion, two million, one hundred twenty-one thousand, two hundred thirty-three".