261045642 has 96 divisors (see below), whose sum is σ = 654768576. Its totient is φ = 68682240.

The previous prime is 261045623. The next prime is 261045667. The reversal of 261045642 is 246540162.

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 47 ways as a sum of consecutive naturals, for example, 159633 + ... + 161259.

It is an arithmetic number, because the mean of its divisors is an integer number (6820506).

Almost surely, 2^261045642 is an apocalyptic number.

261045642 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 261045642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (327384288).

261045642 is an abundant number, since it is smaller than the sum of its proper divisors (393722934).

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

261045642 is a wasteful number, since it uses less digits than its factorization.

261045642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1684 (or 1673 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 261045642 is about 16156.9069440905. The cubic root of 261045642 is about 639.1049026812.

The spelling of 261045642 in words is "two hundred sixty-one million, forty-five thousand, six hundred forty-two".