1988649997 has 2 divisors, whose sum is σ = 1988649998. Its totient is φ = 1988649996.

The previous prime is 1988649979. The next prime is 1988650033. The reversal of 1988649997 is 7999468891.

Together with previous prime (1988649979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1615155721 + 373494276 = 40189^2 + 19326^2 .

It is an emirp because it is prime and its reverse (7999468891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1988649997 - 2⁷ = 1988649869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1988649977) 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, 994324998 + 994324999.

It is an arithmetic number, because the mean of its divisors is an integer number (994324999).

Almost surely, 2^1988649997 is an apocalyptic number.

It is an amenable number.

1988649997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1988649997 is an equidigital number, since it uses as much as digits as its factorization.

1988649997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 70543872, while the sum is 70.

The square root of 1988649997 is about 44594.2821110510. The cubic root of 1988649997 is about 1257.5331758365.

The spelling of 1988649997 in words is "one billion, nine hundred eighty-eight million, six hundred forty-nine thousand, nine hundred ninety-seven".