261632540 has 24 divisors (see below), whose sum is σ = 591692640. Its totient is φ = 96602688.

The previous prime is 261632509. The next prime is 261632543. The reversal of 261632540 is 45236162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261632543) 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 7 ways as a sum of consecutive naturals, for example, 502880 + ... + 503399.

It is an arithmetic number, because the mean of its divisors is an integer number (24653860).

Almost surely, 2^261632540 is an apocalyptic number.

261632540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261632540 is an abundant number, since it is smaller than the sum of its proper divisors (330060100).

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

261632540 is a wasteful number, since it uses less digits than its factorization.

261632540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1006301 (or 1006299 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 261632540 is about 16175.0591961823. The cubic root of 261632540 is about 639.5835017972.

The spelling of 261632540 in words is "two hundred sixty-one million, six hundred thirty-two thousand, five hundred forty".