1261236550065 has 32 divisors (see below), whose sum is σ = 2020706839296. Its totient is φ = 671750526720.

The previous prime is 1261236550003. The next prime is 1261236550069. The reversal of 1261236550065 is 5600556321621.

It is not a de Polignac number, because 1261236550065 - 2⁸ = 1261236549809 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1261236549999 and 1261236550026.

It is not an unprimeable number, because it can be changed into a prime (1261236550069) 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, 48156964 + ... + 48183146.

It is an arithmetic number, because the mean of its divisors is an integer number (63147088728).

Almost surely, 2^{1261236550065} is an apocalyptic number.

1261236550065 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1261236550065 is a deficient number, since it is larger than the sum of its proper divisors (759470289231).

1261236550065 is a wasteful number, since it uses less digits than its factorization.

1261236550065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30409.

The product of its (nonzero) digits is 324000, while the sum is 42.

The spelling of 1261236550065 in words is "one trillion, two hundred sixty-one billion, two hundred thirty-six million, five hundred fifty thousand, sixty-five".