261547380 has 120 divisors (see below), whose sum is σ = 868839048. Its totient is φ = 65636352.

The previous prime is 261547379. The next prime is 261547411. The reversal of 261547380 is 83745162.

261547380 is a `hidden beast` number, since 2 + 615 + 4 + 7 + 38 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 8928144 + 252619236 = 2988^2 + 15894^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 22792 + ... + 32288.

Almost surely, 2^261547380 is an apocalyptic number.

261547380 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 261547380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (434419524).

261547380 is an abundant number, since it is smaller than the sum of its proper divisors (607291668).

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

261547380 is a wasteful number, since it uses less digits than its factorization.

261547380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9535 (or 9524 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 261547380 is about 16172.4265340734. The cubic root of 261547380 is about 639.5141005909.

The spelling of 261547380 in words is "two hundred sixty-one million, five hundred forty-seven thousand, three hundred eighty".