21345511032421 has 4 divisors (see below), whose sum is σ = 21406672955500. Its totient is φ = 21284349109344.

The previous prime is 21345511032389. The next prime is 21345511032533. The reversal of 21345511032421 is 12423011554312.

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 16709994381796 + 4635516650625 = 4087786^2 + 2153025^2 .

It is a cyclic number.

It is not a de Polignac number, because 21345511032421 - 2⁵ = 21345511032389 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 (21345511039421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30580961016 + ... + 30580961713.

It is an arithmetic number, because the mean of its divisors is an integer number (5351668238875).

Almost surely, 2^{21345511032421} is an apocalyptic number.

It is an amenable number.

21345511032421 is a deficient number, since it is larger than the sum of its proper divisors (61161923079).

21345511032421 is an equidigital number, since it uses as much as digits as its factorization.

21345511032421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61161923078.

The product of its (nonzero) digits is 28800, while the sum is 34.

Adding to 21345511032421 its reverse (12423011554312), we get a palindrome (33768522586733).

The spelling of 21345511032421 in words is "twenty-one trillion, three hundred forty-five billion, five hundred eleven million, thirty-two thousand, four hundred twenty-one".