21716916 has 48 divisors (see below), whose sum is σ = 55347264. Its totient is φ = 6587136.

The previous prime is 21716887. The next prime is 21716927. The reversal of 21716916 is 61961712.

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, 10435 + ... + 12341.

It is an arithmetic number, because the mean of its divisors is an integer number (1153068).

Almost surely, 2^21716916 is an apocalyptic number.

21716916 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21716916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27673632).

21716916 is an abundant number, since it is smaller than the sum of its proper divisors (33630348).

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

21716916 is a wasteful number, since it uses less digits than its factorization.

21716916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2000 (or 1998 counting only the distinct ones).

The product of its digits is 4536, while the sum is 33.

The square root of 21716916 is about 4660.1411995775. The cubic root of 21716916 is about 278.9969039109.

The spelling of 21716916 in words is "twenty-one million, seven hundred sixteen thousand, nine hundred sixteen".