20407666 has 4 divisors (see below), whose sum is σ = 30611502. Its totient is φ = 10203832.

The previous prime is 20407643. The next prime is 20407669. The reversal of 20407666 is 66670402.

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., 18792225 + 1615441 = 4335^2 + 1271^2 .

It is not an unprimeable number, because it can be changed into a prime (20407669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5101915 + ... + 5101918.

Almost surely, 2^20407666 is an apocalyptic number.

20407666 is a deficient number, since it is larger than the sum of its proper divisors (10203836).

20407666 is a wasteful number, since it uses less digits than its factorization.

20407666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10203835.

The product of its (nonzero) digits is 12096, while the sum is 31.

The square root of 20407666 is about 4517.4844770071. The cubic root of 20407666 is about 273.2736636884.

The spelling of 20407666 in words is "twenty million, four hundred seven thousand, six hundred sixty-six".