21516704 has 36 divisors (see below), whose sum is σ = 46570482. Its totient is φ = 9778560.

The previous prime is 21516689. The next prime is 21516731. The reversal of 21516704 is 40761512.

It can be written as a sum of positive squares in only one way, i.e., 13337104 + 8179600 = 3652^2 + 2860^2 .

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1094 + ... + 6650.

Almost surely, 2^21516704 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21516704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23285241).

21516704 is an abundant number, since it is smaller than the sum of its proper divisors (25053778).

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

21516704 is a wasteful number, since it uses less digits than its factorization.

21516704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5589 (or 5570 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21516704 is about 4638.6101366681. The cubic root of 21516704 is about 278.1368820240.

The spelling of 21516704 in words is "twenty-one million, five hundred sixteen thousand, seven hundred four".