21009130 has 8 divisors (see below), whose sum is σ = 37816452. Its totient is φ = 8403648.

The previous prime is 21009091. The next prime is 21009139. The reversal of 21009130 is 3190012.

It can be written as a sum of positive squares in 2 ways, for example, as 20548089 + 461041 = 4533^2 + 679^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21009139) 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, 1050447 + ... + 1050466.

Almost surely, 2^21009130 is an apocalyptic number.

21009130 is a deficient number, since it is larger than the sum of its proper divisors (16807322).

21009130 is a wasteful number, since it uses less digits than its factorization.

21009130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2100920.

The product of its (nonzero) digits is 54, while the sum is 16.

The square root of 21009130 is about 4583.5717513747. The cubic root of 21009130 is about 275.9323943496.

Adding to 21009130 its reverse (3190012), we get a palindrome (24199142).

The spelling of 21009130 in words is "twenty-one million, nine thousand, one hundred thirty".