197561887 has 2 divisors, whose sum is σ = 197561888. Its totient is φ = 197561886.

The previous prime is 197561851. The next prime is 197561893. The reversal of 197561887 is 788165791.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-197561887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (197561807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98780943 + 98780944.

It is an arithmetic number, because the mean of its divisors is an integer number (98780944).

Almost surely, 2^197561887 is an apocalyptic number.

197561887 is a deficient number, since it is larger than the sum of its proper divisors (1).

197561887 is an equidigital number, since it uses as much as digits as its factorization.

197561887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 846720, while the sum is 52.

The square root of 197561887 is about 14055.6709907425. The cubic root of 197561887 is about 582.4174634234.

The spelling of 197561887 in words is "one hundred ninety-seven million, five hundred sixty-one thousand, eight hundred eighty-seven".