21130530 has 32 divisors (see below), whose sum is σ = 52351488. Its totient is φ = 5452800.

The previous prime is 21130511. The next prime is 21130573. The reversal of 21130530 is 3503112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a Curzon 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, 10431 + ... + 12290.

It is an arithmetic number, because the mean of its divisors is an integer number (1635984).

Almost surely, 2^21130530 is an apocalyptic number.

21130530 is an abundant number, since it is smaller than the sum of its proper divisors (31220958).

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

21130530 is a wasteful number, since it uses less digits than its factorization.

21130530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22762.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 21130530 is about 4596.7956230400. The cubic root of 21130530 is about 276.4628601769.

Adding to 21130530 its reverse (3503112), we get a palindrome (24633642).

The spelling of 21130530 in words is "twenty-one million, one hundred thirty thousand, five hundred thirty".