20402666 has 8 divisors (see below), whose sum is σ = 31350564. Its totient is φ = 9952480.

The previous prime is 20402663. The next prime is 20402687. The reversal of 20402666 is 66620402.

It can be written as a sum of positive squares in 2 ways, for example, as 15015625 + 5387041 = 3875^2 + 2321^2 .

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 (20402663) 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, 124325 + ... + 124488.

Almost surely, 2^20402666 is an apocalyptic number.

20402666 is a deficient number, since it is larger than the sum of its proper divisors (10947898).

20402666 is a wasteful number, since it uses less digits than its factorization.

20402666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248856.

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 20402666 is about 4516.9310377733. The cubic root of 20402666 is about 273.2513439725.

The spelling of 20402666 in words is "twenty million, four hundred two thousand, six hundred sixty-six".