1187121897 has 24 divisors (see below), whose sum is σ = 1854340488. Its totient is φ = 727488000.

The previous prime is 1187121857. The next prime is 1187121953. The reversal of 1187121897 is 7981217811.

It can be written as a sum of positive squares in 4 ways, for example, as 249292521 + 937829376 = 15789^2 + 30624^2 .

It is not a de Polignac number, because 1187121897 - 2³⁰ = 113380073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1187121847) 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 in 23 ways as a sum of consecutive naturals, for example, 7147 + ... + 49247.

It is an arithmetic number, because the mean of its divisors is an integer number (77264187).

Almost surely, 2^1187121897 is an apocalyptic number.

It is an amenable number.

1187121897 is a deficient number, since it is larger than the sum of its proper divisors (667218591).

1187121897 is a wasteful number, since it uses less digits than its factorization.

1187121897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42361 (or 42358 counting only the distinct ones).

The product of its digits is 56448, while the sum is 45.

The square root of 1187121897 is about 34454.6353485275. The cubic root of 1187121897 is about 1058.8434927222.

The spelling of 1187121897 in words is "one billion, one hundred eighty-seven million, one hundred twenty-one thousand, eight hundred ninety-seven".