21064166 has 4 divisors (see below), whose sum is σ = 31596252. Its totient is φ = 10532082.

The previous prime is 21064163. The next prime is 21064177. The reversal of 21064166 is 66146012.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5266040 + ... + 5266043.

It is an arithmetic number, because the mean of its divisors is an integer number (7899063).

Almost surely, 2^21064166 is an apocalyptic number.

21064166 is a deficient number, since it is larger than the sum of its proper divisors (10532086).

21064166 is a wasteful number, since it uses less digits than its factorization.

21064166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10532085.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21064166 is about 4589.5714396880. The cubic root of 21064166 is about 276.1731305406.

The spelling of 21064166 in words is "twenty-one million, sixty-four thousand, one hundred sixty-six".