1155571997 has 2 divisors, whose sum is σ = 1155571998. Its totient is φ = 1155571996.

The previous prime is 1155571987. The next prime is 1155572009. The reversal of 1155571997 is 7991755511.

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., 602898916 + 552673081 = 24554^2 + 23509^2 .

It is a cyclic number.

It is not a de Polignac number, because 1155571997 - 2⁸ = 1155571741 is a prime.

It is a super-3 number, since 3×1155571997³ (a number of 28 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1155571927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 577785998 + 577785999.

It is an arithmetic number, because the mean of its divisors is an integer number (577785999).

Almost surely, 2^1155571997 is an apocalyptic number.

It is an amenable number.

1155571997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1155571997 is an equidigital number, since it uses as much as digits as its factorization.

1155571997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 496125, while the sum is 50.

The square root of 1155571997 is about 33993.7052555322. The cubic root of 1155571997 is about 1049.3789212887.

The spelling of 1155571997 in words is "one billion, one hundred fifty-five million, five hundred seventy-one thousand, nine hundred ninety-seven".