21130 has 8 divisors (see below), whose sum is σ = 38052. Its totient is φ = 8448.

The previous prime is 21121. The next prime is 21139. The reversal of 21130 is 3112.

It is an interprime number because it is at equal distance from previous prime (21121) and next prime (21139).

It can be written as a sum of positive squares in 2 ways, for example, as 17161 + 3969 = 131^2 + 63^2 .

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

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (21139) by changing a digit.

21130 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1047 + ... + 1066.

2²¹¹³⁰ is an apocalyptic number.

21130 is a deficient number, since it is larger than the sum of its proper divisors (16922).

21130 is a wasteful number, since it uses less digits than its factorization.

21130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2120.

The product of its (nonzero) digits is 6, while the sum is 7.

The square root of 21130 is about 145.3616180427. The cubic root of 21130 is about 27.6460548726.

Adding to 21130 its reverse (3112), we get a palindrome (24242).

It can be divided in two parts, 21 and 130, that added together give a palindrome (151).

The spelling of 21130 in words is "twenty-one thousand, one hundred thirty".