261451611456 has 112 divisors (see below), whose sum is σ = 791236562304. Its totient is φ = 74638411776.

The previous prime is 261451611427. The next prime is 261451611457. The reversal of 261451611456 is 654116154162.

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261451611457) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1550086 + ... + 1710458.

Almost surely, 2^261451611456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261451611456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (395618281152).

261451611456 is an abundant number, since it is smaller than the sum of its proper divisors (529784950848).

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

261451611456 is a wasteful number, since it uses less digits than its factorization.

261451611456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161608 (or 161598 counting only the distinct ones).

The product of its digits is 172800, while the sum is 42.

The spelling of 261451611456 in words is "two hundred sixty-one billion, four hundred fifty-one million, six hundred eleven thousand, four hundred fifty-six".