21580716 has 24 divisors (see below), whose sum is σ = 52545024. Its totient is φ = 6880720.

The previous prime is 21580709. The next prime is 21580717. The reversal of 21580716 is 61708512.

It is not an unprimeable number, because it can be changed into a prime (21580717) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38820 + ... + 39371.

It is an arithmetic number, because the mean of its divisors is an integer number (2189376).

Almost surely, 2^21580716 is an apocalyptic number.

It is an amenable number.

21580716 is an abundant number, since it is smaller than the sum of its proper divisors (30964308).

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

21580716 is a wasteful number, since it uses less digits than its factorization.

21580716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78221 (or 78219 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 21580716 is about 4645.5049241175. The cubic root of 21580716 is about 278.4124271933.

The spelling of 21580716 in words is "twenty-one million, five hundred eighty thousand, seven hundred sixteen".