1187561 has 2 divisors, whose sum is σ = 1187562. Its totient is φ = 1187560.

The previous prime is 1187551. The next prime is 1187567. The reversal of 1187561 is 1657811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 609961 + 577600 = 781^2 + 760^2 .

It is an emirp because it is prime and its reverse (1657811) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1187561 is a prime.

It is a super-2 number, since 2×1187561² = 2820602257442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1187567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 593780 + 593781.

It is an arithmetic number, because the mean of its divisors is an integer number (593781).

2^1187561 is an apocalyptic number.

It is an amenable number.

1187561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1187561 is an equidigital number, since it uses as much as digits as its factorization.

1187561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1680, while the sum is 29.

The square root of 1187561 is about 1089.7527242453. The cubic root of 1187561 is about 105.8974028051.

The spelling of 1187561 in words is "one million, one hundred eighty-seven thousand, five hundred sixty-one".