261164140 has 36 divisors (see below), whose sum is σ = 568045296. Its totient is φ = 100856896.

The previous prime is 261164129. The next prime is 261164153. The reversal of 261164140 is 41461162.

It is an unprimeable number.

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, 9057 + ... + 24583.

It is an arithmetic number, because the mean of its divisors is an integer number (15779036).

Almost surely, 2^261164140 is an apocalyptic number.

261164140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261164140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (284022648).

261164140 is an abundant number, since it is smaller than the sum of its proper divisors (306881156).

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

261164140 is a wasteful number, since it uses less digits than its factorization.

261164140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15594 (or 15563 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 261164140 is about 16160.5736284329. The cubic root of 261164140 is about 639.2015922816.

The spelling of 261164140 in words is "two hundred sixty-one million, one hundred sixty-four thousand, one hundred forty".