21105732673 has 4 divisors (see below), whose sum is σ = 22023373248. Its totient is φ = 20188092100.

The previous prime is 21105732629. The next prime is 21105732677. The reversal of 21105732673 is 37623750112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21105732673 - 2¹³ = 21105724481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21105732677) 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, 458820253 + ... + 458820298.

It is an arithmetic number, because the mean of its divisors is an integer number (5505843312).

Almost surely, 2^21105732673 is an apocalyptic number.

21105732673 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21105732673 is a deficient number, since it is larger than the sum of its proper divisors (917640575).

21105732673 is an equidigital number, since it uses as much as digits as its factorization.

21105732673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917640574.

The product of its (nonzero) digits is 52920, while the sum is 37.

The spelling of 21105732673 in words is "twenty-one billion, one hundred five million, seven hundred thirty-two thousand, six hundred seventy-three".