1988798197 has 4 divisors (see below), whose sum is σ = 1992043180. Its totient is φ = 1985553216.

The previous prime is 1988798177. The next prime is 1988798243. The reversal of 1988798197 is 7918978891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7918978891 = 18439 ⋅429469.

It can be written as a sum of positive squares in 2 ways, for example, as 90801841 + 1897996356 = 9529^2 + 43566^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1988798197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1988798177) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1621572 + ... + 1622797.

It is an arithmetic number, because the mean of its divisors is an integer number (498010795).

Almost surely, 2^1988798197 is an apocalyptic number.

It is an amenable number.

1988798197 is a deficient number, since it is larger than the sum of its proper divisors (3244983).

1988798197 is an equidigital number, since it uses as much as digits as its factorization.

1988798197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3244982.

The product of its digits is 18289152, while the sum is 67.

The square root of 1988798197 is about 44595.9437281016. The cubic root of 1988798197 is about 1257.5644134076.

The spelling of 1988798197 in words is "one billion, nine hundred eighty-eight million, seven hundred ninety-eight thousand, one hundred ninety-seven".