1187907661 has 2 divisors, whose sum is σ = 1187907662. Its totient is φ = 1187907660.

The previous prime is 1187907629. The next prime is 1187907667. The reversal of 1187907661 is 1667097811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 746655625 + 441252036 = 27325^2 + 21006^2 .

It is an emirp because it is prime and its reverse (1667097811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1187907661 - 2⁵ = 1187907629 is a prime.

It is a super-2 number, since 2×1187907661² = 2822249222124981842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1187907667) 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 as a sum of consecutive naturals, namely, 593953830 + 593953831.

It is an arithmetic number, because the mean of its divisors is an integer number (593953831).

Almost surely, 2^1187907661 is an apocalyptic number.

It is an amenable number.

1187907661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1187907661 is an equidigital number, since it uses as much as digits as its factorization.

1187907661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 127008, while the sum is 46.

The square root of 1187907661 is about 34466.0363401422. The cubic root of 1187907661 is about 1059.0770597492.

The spelling of 1187907661 in words is "one billion, one hundred eighty-seven million, nine hundred seven thousand, six hundred sixty-one".