21531673 has 8 divisors (see below), whose sum is σ = 23120640. Its totient is φ = 19978560.

The previous prime is 21531667. The next prime is 21531689. The reversal of 21531673 is 37613512.

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 21531673 - 2⁵ = 21531641 is a prime.

It is a super-2 number, since 2×21531673² = 927225884357858, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21531623) 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, 7713 + ... + 10126.

It is an arithmetic number, because the mean of its divisors is an integer number (2890080).

Almost surely, 2^21531673 is an apocalyptic number.

It is an amenable number.

21531673 is a deficient number, since it is larger than the sum of its proper divisors (1588967).

21531673 is a wasteful number, since it uses less digits than its factorization.

21531673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17927.

The product of its digits is 3780, while the sum is 28.

The square root of 21531673 is about 4640.2233782438. The cubic root of 21531673 is about 278.2013662789.

The spelling of 21531673 in words is "twenty-one million, five hundred thirty-one thousand, six hundred seventy-three".