1231262161 has 4 divisors (see below), whose sum is σ = 1242769392. Its totient is φ = 1219754932.

The previous prime is 1231262159. The next prime is 1231262167. The reversal of 1231262161 is 1612621321.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1612621321 = 5807 ⋅277703.

It is a cyclic number.

It is not a de Polignac number, because 1231262161 - 2¹ = 1231262159 is a prime.

It is a super-2 number, since 2×1231262161² = 3032013018220779842, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1231262167) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5753455 + ... + 5753668.

It is an arithmetic number, because the mean of its divisors is an integer number (310692348).

Almost surely, 2^1231262161 is an apocalyptic number.

It is an amenable number.

1231262161 is a deficient number, since it is larger than the sum of its proper divisors (11507231).

1231262161 is a wasteful number, since it uses less digits than its factorization.

1231262161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11507230.

The product of its digits is 864, while the sum is 25.

The square root of 1231262161 is about 35089.3454056926. The cubic root of 1231262161 is about 1071.8076298762.

Adding to 1231262161 its reverse (1612621321), we get a palindrome (2843883482).

The spelling of 1231262161 in words is "one billion, two hundred thirty-one million, two hundred sixty-two thousand, one hundred sixty-one".