261740240 has 20 divisors (see below), whose sum is σ = 608546244. Its totient is φ = 104696064.

The previous prime is 261740239. The next prime is 261740249. The reversal of 261740240 is 42047162.

It can be written as a sum of positive squares in 2 ways, for example, as 161900176 + 99840064 = 12724^2 + 9992^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261740249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1635797 + ... + 1635956.

Almost surely, 2^261740240 is an apocalyptic number.

261740240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261740240 is an abundant number, since it is smaller than the sum of its proper divisors (346806004).

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

261740240 is a wasteful number, since it uses less digits than its factorization.

261740240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3271766 (or 3271760 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 261740240 is about 16178.3880532023. The cubic root of 261740240 is about 639.6712504306.

The spelling of 261740240 in words is "two hundred sixty-one million, seven hundred forty thousand, two hundred forty".