21673623 has 16 divisors (see below), whose sum is σ = 32209920. Its totient is φ = 12882816.

The previous prime is 21673577. The next prime is 21673633. The reversal of 21673623 is 32637612.

It is not a de Polignac number, because 21673623 - 2⁶ = 21673559 is a prime.

It is a super-2 number, since 2×21673623² = 939491867892258, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21673633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10215 + ... + 12152.

It is an arithmetic number, because the mean of its divisors is an integer number (2013120).

Almost surely, 2^21673623 is an apocalyptic number.

21673623 is a deficient number, since it is larger than the sum of its proper divisors (10536297).

21673623 is a wasteful number, since it uses less digits than its factorization.

21673623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22406.

The product of its digits is 9072, while the sum is 30.

The square root of 21673623 is about 4655.4938513545. The cubic root of 21673623 is about 278.8113857314.

The spelling of 21673623 in words is "twenty-one million, six hundred seventy-three thousand, six hundred twenty-three".