261395164800 has 1440 divisors, whose sum is σ = 1224754914240. Its totient is φ = 54286848000.

The previous prime is 261395164799. The next prime is 261395164801. The reversal of 261395164800 is 8461593162.

261395164800 is a `hidden beast` number, since 2 + 61 + 39 + 516 + 48 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (261395164799) and next prime (261395164801).

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (261395164801) by changing a digit.

It is a polite number, since it can be written in 179 ways as a sum of consecutive naturals, for example, 139707865 + ... + 139709735.

It is an arithmetic number, because the mean of its divisors is an integer number (850524246).

Almost surely, 2^261395164800 is an apocalyptic number.

261395164800 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 261395164800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (612377457120).

261395164800 is an abundant number, since it is smaller than the sum of its proper divisors (963359749440).

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

261395164800 is a wasteful number, since it uses less digits than its factorization.

261395164800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1932 (or 1899 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 261395164800 in words is "two hundred sixty-one billion, three hundred ninety-five million, one hundred sixty-four thousand, eight hundred".