261408 has 48 divisors (see below), whose sum is σ = 786240. Its totient is φ = 74496.

The previous prime is 261407. The next prime is 261427. The reversal of 261408 is 804162.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (261407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 478 + ... + 866.

It is an arithmetic number, because the mean of its divisors is an integer number (16380).

2²⁶¹⁴⁰⁸ is an apocalyptic number.

261408 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 261408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (393120).

261408 is an abundant number, since it is smaller than the sum of its proper divisors (524832).

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

261408 is a wasteful number, since it uses less digits than its factorization.

261408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 401 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 261408 is about 511.2807447968. The cubic root of 261408 is about 63.9400480242.

The spelling of 261408 in words is "two hundred sixty-one thousand, four hundred eight".