21668734 has 4 divisors (see below), whose sum is σ = 32503104. Its totient is φ = 10834366.

The previous prime is 21668729. The next prime is 21668743. The reversal of 21668734 is 43786612.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 21668693 and 21668702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5417182 + ... + 5417185.

It is an arithmetic number, because the mean of its divisors is an integer number (8125776).

Almost surely, 2^21668734 is an apocalyptic number.

21668734 is a deficient number, since it is larger than the sum of its proper divisors (10834370).

21668734 is a wasteful number, since it uses less digits than its factorization.

21668734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10834369.

The product of its digits is 48384, while the sum is 37.

The square root of 21668734 is about 4654.9687431818. The cubic root of 21668734 is about 278.7904199800.

The spelling of 21668734 in words is "twenty-one million, six hundred sixty-eight thousand, seven hundred thirty-four".