21716638 has 8 divisors (see below), whose sum is σ = 32757480. Its totient is φ = 10797480.

The previous prime is 21716627. The next prime is 21716659. The reversal of 21716638 is 83661712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21716638² = 943224732046088, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29973 + ... + 30688.

It is an arithmetic number, because the mean of its divisors is an integer number (4094685).

Almost surely, 2^21716638 is an apocalyptic number.

21716638 is a deficient number, since it is larger than the sum of its proper divisors (11040842).

21716638 is a wasteful number, since it uses less digits than its factorization.

21716638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60842.

The product of its digits is 12096, while the sum is 34.

The square root of 21716638 is about 4660.1113720597. Note that the first 3 decimals coincide. The cubic root of 21716638 is about 278.9957134185.

The spelling of 21716638 in words is "twenty-one million, seven hundred sixteen thousand, six hundred thirty-eight".