261717480 has 80 divisors (see below), whose sum is σ = 879672420. Its totient is φ = 69790464.

The previous prime is 261717461. The next prime is 261717481. The reversal of 261717480 is 84717162.

261717480 is a `hidden beast` number, since 2 + 6 + 171 + 7 + 480 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 241305156 + 20412324 = 15534^2 + 4518^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (261717481) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 37149 + ... + 43628.

Almost surely, 2^261717480 is an apocalyptic number.

261717480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261717480 is an abundant number, since it is smaller than the sum of its proper divisors (617954940).

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

261717480 is a wasteful number, since it uses less digits than its factorization.

261717480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80800 (or 80787 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 261717480 is about 16177.6846303790. The cubic root of 261717480 is about 639.6527087144.

The spelling of 261717480 in words is "two hundred sixty-one million, seven hundred seventeen thousand, four hundred eighty".