20390947 has 2 divisors, whose sum is σ = 20390948. Its totient is φ = 20390946.

The previous prime is 20390941. The next prime is 20391037. The reversal of 20390947 is 74909302.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20390947 - 2¹⁵ = 20358179 is a prime.

It is not a weakly prime, because it can be changed into another prime (20390941) 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, 10195473 + 10195474.

It is an arithmetic number, because the mean of its divisors is an integer number (10195474).

Almost surely, 2^20390947 is an apocalyptic number.

20390947 is a deficient number, since it is larger than the sum of its proper divisors (1).

20390947 is an equidigital number, since it uses as much as digits as its factorization.

20390947 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 20390947 is about 4515.6336210990. The cubic root of 20390947 is about 273.1990167293.

The spelling of 20390947 in words is "twenty million, three hundred ninety thousand, nine hundred forty-seven".