261040840 has 32 divisors (see below), whose sum is σ = 588315960. Its totient is φ = 104243200.

The previous prime is 261040807. The next prime is 261040853. The reversal of 261040840 is 48040162.

It can be written as a sum of positive squares in 4 ways, for example, as 252619236 + 8421604 = 15894^2 + 2902^2 .

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, 20550 + ... + 30730.

Almost surely, 2^261040840 is an apocalyptic number.

261040840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261040840 is an abundant number, since it is smaller than the sum of its proper divisors (327275120).

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

261040840 is a wasteful number, since it uses less digits than its factorization.

261040840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10833 (or 10829 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 261040840 is about 16156.7583382311. The cubic root of 261040840 is about 639.1009838256.

The spelling of 261040840 in words is "two hundred sixty-one million, forty thousand, eight hundred forty".