261216580 has 24 divisors (see below), whose sum is σ = 548858520. Its totient is φ = 104428800.

The previous prime is 261216569. The next prime is 261216583. The reversal of 261216580 is 85612162.

261216580 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 329476 + 260887104 = 574^2 + 16152^2 .

It is not an unprimeable number, because it can be changed into a prime (261216583) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68730 + ... + 72430.

It is an arithmetic number, because the mean of its divisors is an integer number (22869105).

Almost surely, 2^261216580 is an apocalyptic number.

261216580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261216580 is an abundant number, since it is smaller than the sum of its proper divisors (287641940).

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

261216580 is a wasteful number, since it uses less digits than its factorization.

261216580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7239 (or 7237 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 261216580 is about 16162.1960141560. The cubic root of 261216580 is about 639.2443718763.

The spelling of 261216580 in words is "two hundred sixty-one million, two hundred sixteen thousand, five hundred eighty".