1985538197 has 2 divisors, whose sum is σ = 1985538198. Its totient is φ = 1985538196.

The previous prime is 1985538179. The next prime is 1985538211. The reversal of 1985538197 is 7918355891.

Together with previous prime (1985538179) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1918527601 + 67010596 = 43801^2 + 8186^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985538197 - 2²⁰ = 1984489621 is a prime.

It is a congruent number.

It is a weakly prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992769098 + 992769099.

It is an arithmetic number, because the mean of its divisors is an integer number (992769099).

Almost surely, 2^1985538197 is an apocalyptic number.

It is an amenable number.

1985538197 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985538197 is an equidigital number, since it uses as much as digits as its factorization.

1985538197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2721600, while the sum is 56.

The square root of 1985538197 is about 44559.3783282487. The cubic root of 1985538197 is about 1256.8769124395.

The spelling of 1985538197 in words is "one billion, nine hundred eighty-five million, five hundred thirty-eight thousand, one hundred ninety-seven".