21233672021 has 4 divisors (see below), whose sum is σ = 21280963500. Its totient is φ = 21186380544.

The previous prime is 21233672011. The next prime is 21233672029. The reversal of 21233672021 is 12027633212.

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 18455222500 + 2778449521 = 135850^2 + 52711^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21233672021 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 (21233672029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23645066 + ... + 23645963.

It is an arithmetic number, because the mean of its divisors is an integer number (5320240875).

Almost surely, 2^21233672021 is an apocalyptic number.

It is an amenable number.

21233672021 is a deficient number, since it is larger than the sum of its proper divisors (47291479).

21233672021 is an equidigital number, since it uses as much as digits as its factorization.

21233672021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47291478.

The product of its (nonzero) digits is 6048, while the sum is 29.

The spelling of 21233672021 in words is "twenty-one billion, two hundred thirty-three million, six hundred seventy-two thousand, twenty-one".