21070186 has 8 divisors (see below), whose sum is σ = 31631940. Its totient is φ = 10526208.

The previous prime is 21070121. The next prime is 21070201. The reversal of 21070186 is 68107012.

It can be written as a sum of positive squares in 2 ways, for example, as 21022225 + 47961 = 4585^2 + 219^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21070186.

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, 921 + ... + 6556.

Almost surely, 2^21070186 is an apocalyptic number.

21070186 is a deficient number, since it is larger than the sum of its proper divisors (10561754).

21070186 is a wasteful number, since it uses less digits than its factorization.

21070186 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8888.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 21070186 is about 4590.2272274910. The cubic root of 21070186 is about 276.1994375223.

Adding to 21070186 its reverse (68107012), we get a palindrome (89177198).

The spelling of 21070186 in words is "twenty-one million, seventy thousand, one hundred eighty-six".