21673528 has 16 divisors (see below), whose sum is σ = 42777000. Its totient is φ = 10266336.

The previous prime is 21673523. The next prime is 21673559. The reversal of 21673528 is 82537612.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21673493 and 21673502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21673523) 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, 71143 + ... + 71446.

Almost surely, 2^21673528 is an apocalyptic number.

It is an amenable number.

21673528 is a deficient number, since it is larger than the sum of its proper divisors (21103472).

21673528 is a wasteful number, since it uses less digits than its factorization.

21673528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142614 (or 142610 counting only the distinct ones).

The product of its digits is 20160, while the sum is 34.

The square root of 21673528 is about 4655.4836483442. The cubic root of 21673528 is about 278.8109783680.

It can be divided in two parts, 21673 and 528, that added together give a square (22201 = 149²).

The spelling of 21673528 in words is "twenty-one million, six hundred seventy-three thousand, five hundred twenty-eight".