21043670 has 16 divisors (see below), whose sum is σ = 38108448. Its totient is φ = 8366400.

The previous prime is 21043667. The next prime is 21043681. The reversal of 21043670 is 7634012.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 4631 + ... + 7970.

It is an arithmetic number, because the mean of its divisors is an integer number (2381778).

Almost surely, 2^21043670 is an apocalyptic number.

21043670 is a deficient number, since it is larger than the sum of its proper divisors (17064778).

21043670 is a wasteful number, since it uses less digits than its factorization.

21043670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12775.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 21043670 is about 4587.3380080391. The cubic root of 21043670 is about 276.0835268443.

Adding to 21043670 its reverse (7634012), we get a palindrome (28677682).

The spelling of 21043670 in words is "twenty-one million, forty-three thousand, six hundred seventy".