20731666 has 8 divisors (see below), whose sum is σ = 31152240. Its totient is φ = 10347588.

The previous prime is 20731663. The next prime is 20731681. The reversal of 20731666 is 66613702.

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

It is not an unprimeable number, because it can be changed into a prime (20731663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7656 + ... + 10003.

It is an arithmetic number, because the mean of its divisors is an integer number (3894030).

Almost surely, 2^20731666 is an apocalyptic number.

20731666 is a deficient number, since it is larger than the sum of its proper divisors (10420574).

20731666 is a wasteful number, since it uses less digits than its factorization.

20731666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18248.

The product of its (nonzero) digits is 9072, while the sum is 31.

The square root of 20731666 is about 4553.2039269069. The cubic root of 20731666 is about 274.7122764797.

The spelling of 20731666 in words is "twenty million, seven hundred thirty-one thousand, six hundred sixty-six".