21068186 has 4 divisors (see below), whose sum is σ = 31602282. Its totient is φ = 10534092.

The previous prime is 21068183. The next prime is 21068209. The reversal of 21068186 is 68186012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18447025 + 2621161 = 4295^2 + 1619^2 .

It is a super-2 number, since 2×21068186² = 887736922661192, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21068183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5267045 + ... + 5267048.

Almost surely, 2^21068186 is an apocalyptic number.

21068186 is a deficient number, since it is larger than the sum of its proper divisors (10534096).

21068186 is a wasteful number, since it uses less digits than its factorization.

21068186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10534095.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 21068186 is about 4590.0093681822. The cubic root of 21068186 is about 276.1906982172.

The spelling of 21068186 in words is "twenty-one million, sixty-eight thousand, one hundred eighty-six".