21045670 has 8 divisors (see below), whose sum is σ = 37882224. Its totient is φ = 8418264.

The previous prime is 21045649. The next prime is 21045691. The reversal of 21045670 is 7654012.

It is an interprime number because it is at equal distance from previous prime (21045649) and next prime (21045691).

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1052274 + ... + 1052293.

It is an arithmetic number, because the mean of its divisors is an integer number (4735278).

Almost surely, 2^21045670 is an apocalyptic number.

21045670 is a deficient number, since it is larger than the sum of its proper divisors (16836554).

21045670 is a wasteful number, since it uses less digits than its factorization.

21045670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2104574.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 21045670 is about 4587.5559942087. Note that the first 3 decimals coincide. The cubic root of 21045670 is about 276.0922729354.

Adding to 21045670 its reverse (7654012), we get a palindrome (28699682).

The spelling of 21045670 in words is "twenty-one million, forty-five thousand, six hundred seventy".