21130538 has 16 divisors (see below), whose sum is σ = 37237536. Its totient is φ = 8865840.

The previous prime is 21130511. The next prime is 21130573. The reversal of 21130538 is 83503112.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36656 + ... + 37227.

It is an arithmetic number, because the mean of its divisors is an integer number (2327346).

Almost surely, 2^21130538 is an apocalyptic number.

21130538 is a deficient number, since it is larger than the sum of its proper divisors (16106998).

21130538 is a wasteful number, since it uses less digits than its factorization.

21130538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73909.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21130538 is about 4596.7964932113. The cubic root of 21130538 is about 276.4628950664.

The spelling of 21130538 in words is "twenty-one million, one hundred thirty thousand, five hundred thirty-eight".