261400064 has 40 divisors (see below), whose sum is σ = 526190280. Its totient is φ = 129724416.

The previous prime is 261400063. The next prime is 261400123. The reversal of 261400064 is 460004162.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261400063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69332 + ... + 73004.

It is an arithmetic number, because the mean of its divisors is an integer number (13154757).

Almost surely, 2^261400064 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 261400064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (263095140).

261400064 is an abundant number, since it is smaller than the sum of its proper divisors (264790216).

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

261400064 is an equidigital number, since it uses as much as digits as its factorization.

261400064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3830 (or 3814 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 261400064 is about 16167.8713503046. The cubic root of 261400064 is about 639.3940097266.

The spelling of 261400064 in words is "two hundred sixty-one million, four hundred thousand, sixty-four".