1085661557 has 2 divisors, whose sum is σ = 1085661558. Its totient is φ = 1085661556.

The previous prime is 1085661553. The next prime is 1085661623. The reversal of 1085661557 is 7551665801.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1084121476 + 1540081 = 32926^2 + 1241^2 .

It is a cyclic number.

It is not a de Polignac number, because 1085661557 - 2² = 1085661553 is a prime.

It is a super-2 number, since 2×1085661557² = 2357322032695328498, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1085661553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 542830778 + 542830779.

It is an arithmetic number, because the mean of its divisors is an integer number (542830779).

Almost surely, 2^1085661557 is an apocalyptic number.

It is an amenable number.

1085661557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1085661557 is an equidigital number, since it uses as much as digits as its factorization.

1085661557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 252000, while the sum is 44.

The square root of 1085661557 is about 32949.3787043094. The cubic root of 1085661557 is about 1027.7752455325.

It can be divided in two parts, 108 and 5661557, that added together give a palindrome (5661665).

The spelling of 1085661557 in words is "one billion, eighty-five million, six hundred sixty-one thousand, five hundred fifty-seven".