21070080 has 216 divisors, whose sum is σ = 76527360. Its totient is φ = 5345280.

The previous prime is 21070073. The next prime is 21070081. The reversal of 21070080 is 8007012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21070081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 357091 + ... + 357149.

Almost surely, 2^21070080 is an apocalyptic number.

21070080 is a gapful number since it is divisible by the number (20) 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 21070080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38263680).

21070080 is an abundant number, since it is smaller than the sum of its proper divisors (55457280).

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

21070080 is a wasteful number, since it uses less digits than its factorization.

21070080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 21070080 is about 4590.2156812071. The cubic root of 21070080 is about 276.1989743530.

Adding to 21070080 its reverse (8007012), we get a palindrome (29077092).

The spelling of 21070080 in words is "twenty-one million, seventy thousand, eighty".