21130704 has 60 divisors (see below), whose sum is σ = 67587936. Its totient is φ = 6037056.

The previous prime is 21130699. The next prime is 21130727. The reversal of 21130704 is 40703112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent 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 11 ways as a sum of consecutive naturals, for example, 9474 + ... + 11489.

Almost surely, 2^21130704 is an apocalyptic number.

21130704 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21130704 is an abundant number, since it is smaller than the sum of its proper divisors (46457232).

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

21130704 is a wasteful number, since it uses less digits than its factorization.

21130704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20984 (or 20975 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21130704 is about 4596.8145492286. The cubic root of 21130704 is about 276.4636190221.

Adding to 21130704 its reverse (40703112), we get a palindrome (61833816).

The spelling of 21130704 in words is "twenty-one million, one hundred thirty thousand, seven hundred four".