1265500161 has 12 divisors (see below), whose sum is σ = 1828253440. Its totient is φ = 843524280.

The previous prime is 1265500151. The next prime is 1265500177. The reversal of 1265500161 is 1610055621.

It is a happy number.

1265500161 is a `hidden beast` number, since 1 + 2 + 655 + 0 + 0 + 1 + 6 + 1 = 666.

It is not a de Polignac number, because 1265500161 - 2⁶ = 1265500097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1265500151) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94896 + ... + 107406.

It is a Proth number, since it is equal to 9655 ⋅ 2¹⁷ + 1 and 9655 < 2¹⁷.

Almost surely, 2^1265500161 is an apocalyptic number.

It is an amenable number.

1265500161 is a deficient number, since it is larger than the sum of its proper divisors (562753279).

1265500161 is a wasteful number, since it uses less digits than its factorization.

1265500161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23756 (or 23753 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 1265500161 is about 35573.8690754885. The cubic root of 1265500161 is about 1081.6516113277.

Adding to 1265500161 its reverse (1610055621), we get a palindrome (2875555782).

The spelling of 1265500161 in words is "one billion, two hundred sixty-five million, five hundred thousand, one hundred sixty-one".