20445691 has 12 divisors (see below), whose sum is σ = 25036680. Its totient is φ = 16601760.

The previous prime is 20445637. The next prime is 20445697. The reversal of 20445691 is 19654402.

It is not a de Polignac number, because 20445691 - 2⁹ = 20445179 is a prime.

It is a zygodrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (20445697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10050 + ... + 11911.

It is an arithmetic number, because the mean of its divisors is an integer number (2086390).

Almost surely, 2^20445691 is an apocalyptic number.

20445691 is a deficient number, since it is larger than the sum of its proper divisors (4590989).

20445691 is a wasteful number, since it uses less digits than its factorization.

20445691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21994 (or 21987 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 20445691 is about 4521.6911659245. The cubic root of 20445691 is about 273.4432859576.

The spelling of 20445691 in words is "twenty million, four hundred forty-five thousand, six hundred ninety-one".