20545691 has 2 divisors, whose sum is σ = 20545692. Its totient is φ = 20545690.

The previous prime is 20545687. The next prime is 20545697. The reversal of 20545691 is 19654502.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20545691 - 2² = 20545687 is a prime.

It is not a weakly prime, because it can be changed into another prime (20545697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10272845 + 10272846.

It is an arithmetic number, because the mean of its divisors is an integer number (10272846).

Almost surely, 2^20545691 is an apocalyptic number.

20545691 is a deficient number, since it is larger than the sum of its proper divisors (1).

20545691 is an equidigital number, since it uses as much as digits as its factorization.

20545691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 20545691 is about 4532.7354875395. The cubic root of 20545691 is about 273.8883653781. Note that the first 3 decimals are identical.

The spelling of 20545691 in words is "twenty million, five hundred forty-five thousand, six hundred ninety-one".