261543144400044 has 192 divisors, whose sum is σ = 663493135979520. Its totient is φ = 79708518789120.

The previous prime is 261543144400039. The next prime is 261543144400049. The reversal of 261543144400044 is 440004441345162.

It is an interprime number because it is at equal distance from previous prime (261543144400039) and next prime (261543144400049).

It is a junction number, because it is equal to n+sod(n) for n = 261543144399969 and 261543144400005.

It is not an unprimeable number, because it can be changed into a prime (261543144400049) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16721630464 + ... + 16721646104.

It is an arithmetic number, because the mean of its divisors is an integer number (3455693416560).

Almost surely, 2^{261543144400044} 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 261543144400044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (331746567989760).

261543144400044 is an abundant number, since it is smaller than the sum of its proper divisors (401949991579476).

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

261543144400044 is a wasteful number, since it uses less digits than its factorization.

261543144400044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17560 (or 17558 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 42.

The spelling of 261543144400044 in words is "two hundred sixty-one trillion, five hundred forty-three billion, one hundred forty-four million, four hundred thousand, forty-four".