1261113161 has 32 divisors (see below), whose sum is σ = 1645056000. Its totient is φ = 937442880.

The previous prime is 1261113121. The next prime is 1261113167. The reversal of 1261113161 is 1613111621.

It is a happy number.

It is not a de Polignac number, because 1261113161 - 2⁶ = 1261113097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is not an unprimeable number, because it can be changed into a prime (1261113167) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 900740 + ... + 902138.

It is an arithmetic number, because the mean of its divisors is an integer number (51408000).

Almost surely, 2^1261113161 is an apocalyptic number.

1261113161 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1261113161 is a deficient number, since it is larger than the sum of its proper divisors (383942839).

1261113161 is a wasteful number, since it uses less digits than its factorization.

1261113161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1949.

The product of its digits is 216, while the sum is 23.

The square root of 1261113161 is about 35512.1551162415. The cubic root of 1261113161 is about 1080.4002748694.

Adding to 1261113161 its reverse (1613111621), we get a palindrome (2874224782).

The spelling of 1261113161 in words is "one billion, two hundred sixty-one million, one hundred thirteen thousand, one hundred sixty-one".