21673516 has 12 divisors (see below), whose sum is σ = 37963800. Its totient is φ = 10826720.

The previous prime is 21673511. The next prime is 21673517. The reversal of 21673516 is 61537612.

It is not an unprimeable number, because it can be changed into a prime (21673511) 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, 4560 + ... + 8008.

It is an arithmetic number, because the mean of its divisors is an integer number (3163650).

Almost surely, 2^21673516 is an apocalyptic number.

It is an amenable number.

21673516 is a deficient number, since it is larger than the sum of its proper divisors (16290284).

21673516 is a wasteful number, since it uses less digits than its factorization.

21673516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5024 (or 5022 counting only the distinct ones).

The product of its digits is 7560, while the sum is 31.

The square root of 21673516 is about 4655.4823595413. The cubic root of 21673516 is about 278.8109269115.

The spelling of 21673516 in words is "twenty-one million, six hundred seventy-three thousand, five hundred sixteen".