21133730 has 8 divisors (see below), whose sum is σ = 38040732. Its totient is φ = 8453488.

The previous prime is 21133727. The next prime is 21133733. The reversal of 21133730 is 3733112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21133727) and next prime (21133733).

It can be written as a sum of positive squares in 2 ways, for example, as 17397241 + 3736489 = 4171^2 + 1933^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21133733) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1056677 + ... + 1056696.

Almost surely, 2^21133730 is an apocalyptic number.

21133730 is a deficient number, since it is larger than the sum of its proper divisors (16907002).

21133730 is a wasteful number, since it uses less digits than its factorization.

21133730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2113380.

The product of its (nonzero) digits is 378, while the sum is 20.

The square root of 21133730 is about 4597.1436784160. The cubic root of 21133730 is about 276.4768152851.

Adding to 21133730 its reverse (3733112), we get a palindrome (24866842).

The spelling of 21133730 in words is "twenty-one million, one hundred thirty-three thousand, seven hundred thirty".