21150730 has 8 divisors (see below), whose sum is σ = 38071332. Its totient is φ = 8460288.

The previous prime is 21150719. The next prime is 21150739. The reversal of 21150730 is 3705112.

It can be written as a sum of positive squares in 2 ways, for example, as 21058921 + 91809 = 4589^2 + 303^2 .

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

It is a zygodrome in base 4.

It is a junction number, because it is equal to n+sod(n) for n = 21150698 and 21150707.

It is not an unprimeable number, because it can be changed into a prime (21150739) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1057527 + ... + 1057546.

Almost surely, 2^21150730 is an apocalyptic number.

21150730 is a deficient number, since it is larger than the sum of its proper divisors (16920602).

21150730 is a wasteful number, since it uses less digits than its factorization.

21150730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2115080.

The product of its (nonzero) digits is 210, while the sum is 19.

The square root of 21150730 is about 4598.9922809242. The cubic root of 21150730 is about 276.5509281868.

Adding to 21150730 its reverse (3705112), we get a palindrome (24855842).

The spelling of 21150730 in words is "twenty-one million, one hundred fifty thousand, seven hundred thirty".