20013997 has 2 divisors, whose sum is σ = 20013998. Its totient is φ = 20013996.

The previous prime is 20013991. The next prime is 20014009. The reversal of 20013997 is 79931002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19193161 + 820836 = 4381^2 + 906^2 .

It is a cyclic number.

It is not a de Polignac number, because 20013997 - 2¹⁵ = 19981229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20013991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10006998 + 10006999.

It is an arithmetic number, because the mean of its divisors is an integer number (10006999).

Almost surely, 2^20013997 is an apocalyptic number.

It is an amenable number.

20013997 is a deficient number, since it is larger than the sum of its proper divisors (1).

20013997 is an equidigital number, since it uses as much as digits as its factorization.

20013997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 20013997 is about 4473.7005934685. The cubic root of 20013997 is about 271.5050697320.

Adding to 20013997 its reverse (79931002), we get a palindrome (99944999).

It can be divided in two parts, 2001 and 3997, that multiplied together give a palindrome (7997997).

The spelling of 20013997 in words is "twenty million, thirteen thousand, nine hundred ninety-seven".