21019280 has 20 divisors (see below), whose sum is σ = 48870012. Its totient is φ = 8407680.

The previous prime is 21019279. The next prime is 21019283. The reversal of 21019280 is 8291012.

It can be written as a sum of positive squares in 2 ways, for example, as 5400976 + 15618304 = 2324^2 + 3952^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (21019283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131291 + ... + 131450.

Almost surely, 2^21019280 is an apocalyptic number.

21019280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21019280 is an abundant number, since it is smaller than the sum of its proper divisors (27850732).

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

21019280 is a wasteful number, since it uses less digits than its factorization.

21019280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262754 (or 262748 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 21019280 is about 4584.6788328082. The cubic root of 21019280 is about 275.9768236507.

The spelling of 21019280 in words is "twenty-one million, nineteen thousand, two hundred eighty".