21715080 has 32 divisors (see below), whose sum is σ = 65145600. Its totient is φ = 5790656.

The previous prime is 21715063. The next prime is 21715087. The reversal of 21715080 is 8051712.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21715080.

It is not an unprimeable number, because it can be changed into a prime (21715087) 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, 90360 + ... + 90599.

It is an arithmetic number, because the mean of its divisors is an integer number (2035800).

Almost surely, 2^21715080 is an apocalyptic number.

21715080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21715080 is an abundant number, since it is smaller than the sum of its proper divisors (43430520).

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

21715080 is a wasteful number, since it uses less digits than its factorization.

21715080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180973 (or 180969 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 21715080 is about 4659.9442056746. The cubic root of 21715080 is about 278.9890413342.

Adding to 21715080 its reverse (8051712), we get a palindrome (29766792).

The spelling of 21715080 in words is "twenty-one million, seven hundred fifteen thousand, eighty".