261544955840 has 84 divisors (see below), whose sum is σ = 724486243176. Its totient is φ = 89672550912.

The previous prime is 261544955831. The next prime is 261544955843. The reversal of 261544955840 is 48559445162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261544955843) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8324402 + ... + 8355761.

Almost surely, 2^261544955840 is an apocalyptic number.

261544955840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261544955840 is an abundant number, since it is smaller than the sum of its proper divisors (462941287336).

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

261544955840 is a wasteful number, since it uses less digits than its factorization.

261544955840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16680194 (or 16680177 counting only the distinct ones).

The product of its (nonzero) digits is 6912000, while the sum is 53.

The spelling of 261544955840 in words is "two hundred sixty-one billion, five hundred forty-four million, nine hundred fifty-five thousand, eight hundred forty".