1261385262858 has 64 divisors (see below), whose sum is σ = 2917479029760. Its totient is φ = 356112028800.

The previous prime is 1261385262827. The next prime is 1261385262869. The reversal of 1261385262858 is 8582625831621.

It is a junction number, because it is equal to n+sod(n) for n = 1261385262798 and 1261385262807.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5612673 + ... + 5833083.

It is an arithmetic number, because the mean of its divisors is an integer number (45585609840).

Almost surely, 2^{1261385262858} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261385262858, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1458739514880).

1261385262858 is an abundant number, since it is smaller than the sum of its proper divisors (1656093766902).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1261385262858 is a wasteful number, since it uses less digits than its factorization.

1261385262858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222043.

The product of its digits is 11059200, while the sum is 57.

The spelling of 1261385262858 in words is "one trillion, two hundred sixty-one billion, three hundred eighty-five million, two hundred sixty-two thousand, eight hundred fifty-eight".