261308720 has 40 divisors (see below), whose sum is σ = 620478144. Its totient is φ = 102298112.

The previous prime is 261308711. The next prime is 261308737. The reversal of 261308720 is 27803162.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

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, 30989 + ... + 38508.

Almost surely, 2^261308720 is an apocalyptic number.

261308720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261308720 is an abundant number, since it is smaller than the sum of its proper divisors (359169424).

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

261308720 is a wasteful number, since it uses less digits than its factorization.

261308720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69557 (or 69551 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 261308720 is about 16165.0462418145. The cubic root of 261308720 is about 639.3195241407.

The spelling of 261308720 in words is "two hundred sixty-one million, three hundred eight thousand, seven hundred twenty".