261490860 has 36 divisors (see below), whose sum is σ = 793189488. Its totient is φ = 69730848.

The previous prime is 261490849. The next prime is 261490861. The reversal of 261490860 is 68094162.

It is a tau number, because it is divible by the number of its divisors (36).

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 (261490861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 726184 + ... + 726543.

Almost surely, 2^261490860 is an apocalyptic number.

261490860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261490860 is an abundant number, since it is smaller than the sum of its proper divisors (531698628).

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

261490860 is a wasteful number, since it uses less digits than its factorization.

261490860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1452742 (or 1452737 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 261490860 is about 16170.6790209935. The cubic root of 261490860 is about 639.4680312568.

The spelling of 261490860 in words is "two hundred sixty-one million, four hundred ninety thousand, eight hundred sixty".