1156661557 has 2 divisors, whose sum is σ = 1156661558. Its totient is φ = 1156661556.

The previous prime is 1156661531. The next prime is 1156661563. The reversal of 1156661557 is 7551666511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 746437041 + 410224516 = 27321^2 + 20254^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1156661557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1156667557) 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, 578330778 + 578330779.

It is an arithmetic number, because the mean of its divisors is an integer number (578330779).

Almost surely, 2^1156661557 is an apocalyptic number.

It is an amenable number.

1156661557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1156661557 is an equidigital number, since it uses as much as digits as its factorization.

1156661557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 189000, while the sum is 43.

The square root of 1156661557 is about 34009.7273879107. The cubic root of 1156661557 is about 1049.7086287524.

The spelling of 1156661557 in words is "one billion, one hundred fifty-six million, six hundred sixty-one thousand, five hundred fifty-seven".