21412366021 has 4 divisors (see below), whose sum is σ = 22150723500. Its totient is φ = 20674008544.

The previous prime is 21412366013. The next prime is 21412366039. The reversal of 21412366021 is 12066321412.

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 17138475396 + 4273890625 = 130914^2 + 65375^2 .

It is a cyclic number.

It is not a de Polignac number, because 21412366021 - 2³ = 21412366013 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 (21412366121) 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, 369178696 + ... + 369178753.

It is an arithmetic number, because the mean of its divisors is an integer number (5537680875).

Almost surely, 2^21412366021 is an apocalyptic number.

It is an amenable number.

21412366021 is a deficient number, since it is larger than the sum of its proper divisors (738357479).

21412366021 is an equidigital number, since it uses as much as digits as its factorization.

21412366021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 738357478.

The product of its (nonzero) digits is 3456, while the sum is 28.

Adding to 21412366021 its reverse (12066321412), we get a palindrome (33478687433).

The spelling of 21412366021 in words is "twenty-one billion, four hundred twelve million, three hundred sixty-six thousand, twenty-one".