261645384 has 128 divisors (see below), whose sum is σ = 878330880. Its totient is φ = 62726400.

The previous prime is 261645379. The next prime is 261645403. The reversal of 261645384 is 483546162.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18579 + ... + 29469.

It is an arithmetic number, because the mean of its divisors is an integer number (6861960).

Almost surely, 2^261645384 is an apocalyptic number.

261645384 is a gapful number since it is divisible by the number (24) 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 261645384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (439165440).

261645384 is an abundant number, since it is smaller than the sum of its proper divisors (616685496).

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

261645384 is a wasteful number, since it uses less digits than its factorization.

261645384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10931 (or 10927 counting only the distinct ones).

The product of its digits is 138240, while the sum is 39.

The square root of 261645384 is about 16175.4562223141. The cubic root of 261645384 is about 639.5939677177.

The spelling of 261645384 in words is "two hundred sixty-one million, six hundred forty-five thousand, three hundred eighty-four".