21716628 has 36 divisors (see below), whose sum is σ = 51539040. Its totient is φ = 7117040.

The previous prime is 21716627. The next prime is 21716659. The reversal of 21716628 is 82661712.

It is a super-2 number, since 2×21716628² = 943223863380768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60313 + ... + 60671.

It is an arithmetic number, because the mean of its divisors is an integer number (1431640).

Almost surely, 2^21716628 is an apocalyptic number.

It is an amenable number.

21716628 is an abundant number, since it is smaller than the sum of its proper divisors (29822412).

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

21716628 is a wasteful number, since it uses less digits than its factorization.

21716628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508 (or 435 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 21716628 is about 4660.1102991238. The cubic root of 21716628 is about 278.9956705948.

The spelling of 21716628 in words is "twenty-one million, seven hundred sixteen thousand, six hundred twenty-eight".