21510130 has 8 divisors (see below), whose sum is σ = 38718252. Its totient is φ = 8604048.

The previous prime is 21510127. The next prime is 21510131. The reversal of 21510130 is 3101512.

21510130 = 569² + 570² + ... + 628².

It can be written as a sum of positive squares in 2 ways, for example, as 19989841 + 1520289 = 4471^2 + 1233^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21510130.

It is not an unprimeable number, because it can be changed into a prime (21510131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1075497 + ... + 1075516.

Almost surely, 2^21510130 is an apocalyptic number.

21510130 is a deficient number, since it is larger than the sum of its proper divisors (17208122).

21510130 is a wasteful number, since it uses less digits than its factorization.

21510130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2151020.

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 21510130 is about 4637.9014651025. The cubic root of 21510130 is about 278.1085527454.

Adding to 21510130 its reverse (3101512), we get a palindrome (24611642).

The spelling of 21510130 in words is "twenty-one million, five hundred ten thousand, one hundred thirty".