261639168 has 176 divisors, whose sum is σ = 833210880. Its totient is φ = 71503872.

The previous prime is 261639151. The next prime is 261639193. The reversal of 261639168 is 861936162.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11375605 + ... + 11375627.

Almost surely, 2^261639168 is an apocalyptic number.

261639168 is a gapful number since it is divisible by the number (28) 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 261639168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (416605440).

261639168 is an abundant number, since it is smaller than the sum of its proper divisors (571571712).

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

261639168 is an frugal number, since it uses more digits than its factorization.

261639168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99 (or 35 counting only the distinct ones).

The product of its digits is 93312, while the sum is 42.

The square root of 261639168 is about 16175.2640782152. The cubic root of 261639168 is about 639.5889026591.

261639168 divided by its sum of digits (42) gives a cube (6229504 = 184³).

The spelling of 261639168 in words is "two hundred sixty-one million, six hundred thirty-nine thousand, one hundred sixty-eight".