21106730 has 8 divisors (see below), whose sum is σ = 37992132. Its totient is φ = 8442688.

The previous prime is 21106721. The next prime is 21106763. The reversal of 21106730 is 3760112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20187049 + 919681 = 4493^2 + 959^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1055327 + ... + 1055346.

Almost surely, 2^21106730 is an apocalyptic number.

21106730 is a deficient number, since it is larger than the sum of its proper divisors (16885402).

21106730 is a wasteful number, since it uses less digits than its factorization.

21106730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2110680.

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 21106730 is about 4594.2061338168. The cubic root of 21106730 is about 276.3590248263.

Adding to 21106730 its reverse (3760112), we get a palindrome (24866842).

The spelling of 21106730 in words is "twenty-one million, one hundred six thousand, seven hundred thirty".