21916686 has 32 divisors (see below), whose sum is σ = 48182400. Its totient is φ = 6590880.

The previous prime is 21916669. The next prime is 21916753. The reversal of 21916686 is 68661912.

It is a super-2 number, since 2×21916686² = 960682250445192, 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 15 ways as a sum of consecutive naturals, for example, 7980 + ... + 10368.

It is an arithmetic number, because the mean of its divisors is an integer number (1505700).

Almost surely, 2^21916686 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21916686, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24091200).

21916686 is an abundant number, since it is smaller than the sum of its proper divisors (26265714).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21916686 is a wasteful number, since it uses less digits than its factorization.

21916686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2544.

The product of its digits is 31104, while the sum is 39.

The square root of 21916686 is about 4681.5260332503. The cubic root of 21916686 is about 279.8497748580.

The spelling of 21916686 in words is "twenty-one million, nine hundred sixteen thousand, six hundred eighty-six".