197978989 has 16 divisors (see below), whose sum is σ = 222154240. Its totient is φ = 175193280.

The previous prime is 197978983. The next prime is 197979013. The reversal of 197978989 is 989879791.

It is a cyclic number.

It is not a de Polignac number, because 197978989 - 2⁷ = 197978861 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 (197978983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41674 + ... + 46180.

It is an arithmetic number, because the mean of its divisors is an integer number (13884640).

Almost surely, 2^197978989 is an apocalyptic number.

It is an amenable number.

197978989 is a deficient number, since it is larger than the sum of its proper divisors (24175251).

197978989 is a wasteful number, since it uses less digits than its factorization.

197978989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4660.

The product of its digits is 20575296, while the sum is 67.

The square root of 197978989 is about 14070.5006662876. The cubic root of 197978989 is about 582.8270510767.

The spelling of 197978989 in words is "one hundred ninety-seven million, nine hundred seventy-eight thousand, nine hundred eighty-nine".