261553772444320 has 192 divisors, whose sum is σ = 642906443692800. Its totient is φ = 100475543347200.

The previous prime is 261553772444317. The next prime is 261553772444401. The reversal of 261553772444320 is 23444277355162.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 299047006 + ... + 299920354.

It is an arithmetic number, because the mean of its divisors is an integer number (3348471060900).

Almost surely, 2^{261553772444320} is an apocalyptic number.

261553772444320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261553772444320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (321453221846400).

261553772444320 is an abundant number, since it is smaller than the sum of its proper divisors (381352671248480).

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

261553772444320 is a wasteful number, since it uses less digits than its factorization.

261553772444320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874119 (or 874111 counting only the distinct ones).

The product of its (nonzero) digits is 33868800, while the sum is 55.

The spelling of 261553772444320 in words is "two hundred sixty-one trillion, five hundred fifty-three billion, seven hundred seventy-two million, four hundred forty-four thousand, three hundred twenty".