21707830 has 8 divisors (see below), whose sum is σ = 39074112. Its totient is φ = 8683128.

The previous prime is 21707797. The next prime is 21707849. The reversal of 21707830 is 3870712.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

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, 1085382 + ... + 1085401.

It is an arithmetic number, because the mean of its divisors is an integer number (4884264).

Almost surely, 2^21707830 is an apocalyptic number.

21707830 is a deficient number, since it is larger than the sum of its proper divisors (17366282).

21707830 is a wasteful number, since it uses less digits than its factorization.

21707830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2170790.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 21707830 is about 4659.1662344244. The cubic root of 21707830 is about 278.9579892467.

It can be divided in two parts, 2170 and 7830, that added together give a 4-th power (10000 = 10⁴).

The spelling of 21707830 in words is "twenty-one million, seven hundred seven thousand, eight hundred thirty".