20864566 has 4 divisors (see below), whose sum is σ = 31296852. Its totient is φ = 10432282.

The previous prime is 20864539. The next prime is 20864573. The reversal of 20864566 is 66546802.

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

It is a super-2 number, since 2×20864566² = 870660228736712, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5216140 + ... + 5216143.

It is an arithmetic number, because the mean of its divisors is an integer number (7824213).

Almost surely, 2^20864566 is an apocalyptic number.

20864566 is a deficient number, since it is larger than the sum of its proper divisors (10432286).

20864566 is a wasteful number, since it uses less digits than its factorization.

20864566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10432285.

The product of its (nonzero) digits is 69120, while the sum is 37.

The square root of 20864566 is about 4567.7747317485. The cubic root of 20864566 is about 275.2980394087.

The spelling of 20864566 in words is "twenty million, eight hundred sixty-four thousand, five hundred sixty-six".