20815946897 has 2 divisors, whose sum is σ = 20815946898. Its totient is φ = 20815946896.

The previous prime is 20815946857. The next prime is 20815946911. The reversal of 20815946897 is 79864951802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12615557761 + 8200389136 = 112319^2 + 90556^2 .

It is a cyclic number.

It is not a de Polignac number, because 20815946897 - 2¹² = 20815942801 is a prime.

It is not a weakly prime, because it can be changed into another prime (20815946857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10407973448 + 10407973449.

It is an arithmetic number, because the mean of its divisors is an integer number (10407973449).

Almost surely, 2^20815946897 is an apocalyptic number.

It is an amenable number.

20815946897 is a deficient number, since it is larger than the sum of its proper divisors (1).

20815946897 is an equidigital number, since it uses as much as digits as its factorization.

20815946897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8709120, while the sum is 59.

The spelling of 20815946897 in words is "twenty billion, eight hundred fifteen million, nine hundred forty-six thousand, eight hundred ninety-seven".