21546541673 has 4 divisors (see below), whose sum is σ = 21624327300. Its totient is φ = 21468756048.

The previous prime is 21546541669. The next prime is 21546541697. The reversal of 21546541673 is 37614564512.

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 2620211344 + 18926330329 = 51188^2 + 137573^2 .

It is a cyclic number.

It is not a de Polignac number, because 21546541673 - 2² = 21546541669 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21546541603) 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, 38892398 + ... + 38892951.

It is an arithmetic number, because the mean of its divisors is an integer number (5406081825).

Almost surely, 2^21546541673 is an apocalyptic number.

It is an amenable number.

21546541673 is a deficient number, since it is larger than the sum of its proper divisors (77785627).

21546541673 is an equidigital number, since it uses as much as digits as its factorization.

21546541673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77785626.

The product of its digits is 604800, while the sum is 44.

The spelling of 21546541673 in words is "twenty-one billion, five hundred forty-six million, five hundred forty-one thousand, six hundred seventy-three".