21373616452421 has 4 divisors (see below), whose sum is σ = 21373783664844. Its totient is φ = 21373449240000.

The previous prime is 21373616452403. The next prime is 21373616452457. The reversal of 21373616452421 is 12425461637312.

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 19260994900225 + 2112621552196 = 4388735^2 + 1453486^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21373616452421 is a prime.

It is a super-3 number, since 3×21373616452421³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21373616052421) 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, 83414330 + ... + 83670171.

It is an arithmetic number, because the mean of its divisors is an integer number (5343445916211).

Almost surely, 2^{21373616452421} is an apocalyptic number.

It is an amenable number.

21373616452421 is a deficient number, since it is larger than the sum of its proper divisors (167212423).

21373616452421 is a wasteful number, since it uses less digits than its factorization.

21373616452421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167212422.

The product of its digits is 1451520, while the sum is 47.

The spelling of 21373616452421 in words is "twenty-one trillion, three hundred seventy-three billion, six hundred sixteen million, four hundred fifty-two thousand, four hundred twenty-one".