21073810 has 8 divisors (see below), whose sum is σ = 37932876. Its totient is φ = 8429520.

The previous prime is 21073799. The next prime is 21073837. The reversal of 21073810 is 1837012.

It can be written as a sum of positive squares in 2 ways, for example, as 19386409 + 1687401 = 4403^2 + 1299^2 .

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

It is a super-2 number, since 2×21073810² = 888210935832200, which contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 1053681 + ... + 1053700.

Almost surely, 2^21073810 is an apocalyptic number.

21073810 is a deficient number, since it is larger than the sum of its proper divisors (16859066).

21073810 is a wasteful number, since it uses less digits than its factorization.

21073810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2107388.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21073810 is about 4590.6219622182. The cubic root of 21073810 is about 276.2152717344.

The spelling of 21073810 in words is "twenty-one million, seventy-three thousand, eight hundred ten".