1261456161 has 16 divisors (see below), whose sum is σ = 1945380864. Its totient is φ = 712146384.

The previous prime is 1261456129. The next prime is 1261456187. The reversal of 1261456161 is 1616541621.

It is not a de Polignac number, because 1261456161 - 2⁵ = 1261456129 is a prime.

It is a super-2 number, since 2×1261456161² = 3182543292249715842, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1261456561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 360121 + ... + 363606.

It is an arithmetic number, because the mean of its divisors is an integer number (121586304).

Almost surely, 2^1261456161 is an apocalyptic number.

It is an amenable number.

1261456161 is a deficient number, since it is larger than the sum of its proper divisors (683924703).

1261456161 is an equidigital number, since it uses as much as digits as its factorization.

1261456161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 723820.

The product of its digits is 8640, while the sum is 33.

The square root of 1261456161 is about 35516.9841202769. The cubic root of 1261456161 is about 1080.4982157770.

Adding to 1261456161 its reverse (1616541621), we get a palindrome (2877997782).

The spelling of 1261456161 in words is "one billion, two hundred sixty-one million, four hundred fifty-six thousand, one hundred sixty-one".