1988777897 has 2 divisors, whose sum is σ = 1988777898. Its totient is φ = 1988777896.

The previous prime is 1988777873. The next prime is 1988777983. The reversal of 1988777897 is 7987778891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1928000281 + 60777616 = 43909^2 + 7796^2 .

It is a cyclic number.

It is not a de Polignac number, because 1988777897 - 2²⁰ = 1987729321 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1988777897.

It is not a weakly prime, because it can be changed into another prime (1988777867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994388948 + 994388949.

It is an arithmetic number, because the mean of its divisors is an integer number (994388949).

Almost surely, 2^1988777897 is an apocalyptic number.

It is an amenable number.

1988777897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1988777897 is an equidigital number, since it uses as much as digits as its factorization.

1988777897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 99574272, while the sum is 71.

The square root of 1988777897 is about 44595.7161283458. The cubic root of 1988777897 is about 1257.5601346688.

The spelling of 1988777897 in words is "one billion, nine hundred eighty-eight million, seven hundred seventy-seven thousand, eight hundred ninety-seven".