21130445 has 16 divisors (see below), whose sum is σ = 30240000. Its totient is φ = 13858944.

The previous prime is 21130423. The next prime is 21130453. The reversal of 21130445 is 54403112.

It is a cyclic number.

It is not a de Polignac number, because 21130445 - 2¹² = 21126349 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12320 + ... + 13929.

It is an arithmetic number, because the mean of its divisors is an integer number (1890000).

Almost surely, 2^21130445 is an apocalyptic number.

It is an amenable number.

21130445 is a deficient number, since it is larger than the sum of its proper divisors (9109555).

21130445 is a wasteful number, since it uses less digits than its factorization.

21130445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26284.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21130445 is about 4596.7863774598. The cubic root of 21130445 is about 276.4624894751.

Adding to 21130445 its reverse (54403112), we get a palindrome (75533557).

The spelling of 21130445 in words is "twenty-one million, one hundred thirty thousand, four hundred forty-five".