261464240 has 20 divisors (see below), whose sum is σ = 607904544. Its totient is φ = 104585664.

The previous prime is 261464227. The next prime is 261464249. The reversal of 261464240 is 42464162.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (261464249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1634072 + ... + 1634231.

Almost surely, 2^261464240 is an apocalyptic number.

261464240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261464240 is an abundant number, since it is smaller than the sum of its proper divisors (346440304).

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

261464240 is a wasteful number, since it uses less digits than its factorization.

261464240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3268316 (or 3268310 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 29.

The square root of 261464240 is about 16169.8559053567. The cubic root of 261464240 is about 639.4463310507.

The spelling of 261464240 in words is "two hundred sixty-one million, four hundred sixty-four thousand, two hundred forty".