21172673 has 8 divisors (see below), whose sum is σ = 22456896. Its totient is φ = 19918800.

The previous prime is 21172663. The next prime is 21172691. The reversal of 21172673 is 37627112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21172673 - 2¹⁰ = 21171649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21172643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6143 + ... + 8948.

It is an arithmetic number, because the mean of its divisors is an integer number (2807112).

Almost surely, 2^21172673 is an apocalyptic number.

21172673 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21172673 is a deficient number, since it is larger than the sum of its proper divisors (1284223).

21172673 is a wasteful number, since it uses less digits than its factorization.

21172673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15175.

The product of its digits is 3528, while the sum is 29.

The square root of 21172673 is about 4601.3772938111. The cubic root of 21172673 is about 276.6465318164.

Adding to 21172673 its reverse (37627112), we get a palindrome (58799785).

The spelling of 21172673 in words is "twenty-one million, one hundred seventy-two thousand, six hundred seventy-three".