261512440 has 32 divisors (see below), whose sum is σ = 672461280. Its totient is φ = 89661312.

The previous prime is 261512359. The next prime is 261512453. The reversal of 261512440 is 44215162.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 466707 + ... + 467266.

It is an arithmetic number, because the mean of its divisors is an integer number (21014415).

Almost surely, 2^261512440 is an apocalyptic number.

261512440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261512440 is an abundant number, since it is smaller than the sum of its proper divisors (410948840).

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

261512440 is a wasteful number, since it uses less digits than its factorization.

261512440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 933991 (or 933987 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 261512440 is about 16171.3462643034. The cubic root of 261512440 is about 639.4856218531.

The spelling of 261512440 in words is "two hundred sixty-one million, five hundred twelve thousand, four hundred forty".