261861830 has 32 divisors (see below), whose sum is σ = 483725088. Its totient is φ = 102009600.

The previous prime is 261861827. The next prime is 261861833. The reversal of 261861830 is 38168162.

It is an interprime number because it is at equal distance from previous prime (261861827) and next prime (261861833).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261861833) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 197570 + ... + 198890.

It is an arithmetic number, because the mean of its divisors is an integer number (15116409).

Almost surely, 2^261861830 is an apocalyptic number.

261861830 is a deficient number, since it is larger than the sum of its proper divisors (221863258).

261861830 is a wasteful number, since it uses less digits than its factorization.

261861830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1832.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 261861830 is about 16182.1454078253. The cubic root of 261861830 is about 639.7702870259.

The spelling of 261861830 in words is "two hundred sixty-one million, eight hundred sixty-one thousand, eight hundred thirty".