261747840 has 64 divisors (see below), whose sum is σ = 834327360. Its totient is φ = 69798912.

The previous prime is 261747809. The next prime is 261747859. The reversal of 261747840 is 48747162.

261747840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66244 + ... + 70083.

It is an arithmetic number, because the mean of its divisors is an integer number (13036365).

Almost surely, 2^261747840 is an apocalyptic number.

261747840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261747840 is an abundant number, since it is smaller than the sum of its proper divisors (572579520).

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

261747840 is a wasteful number, since it uses less digits than its factorization.

261747840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136349 (or 136337 counting only the distinct ones).

The product of its (nonzero) digits is 75264, while the sum is 39.

The square root of 261747840 is about 16178.6229327468. The cubic root of 261747840 is about 639.6774416254.

The spelling of 261747840 in words is "two hundred sixty-one million, seven hundred forty-seven thousand, eight hundred forty".