261618984 has 240 divisors, whose sum is σ = 855866880. Its totient is φ = 74027520.

The previous prime is 261618983. The next prime is 261619049. The reversal of 261618984 is 489816162.

261618984 is a `hidden beast` number, since 26 + 1 + 618 + 9 + 8 + 4 = 666.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (261618983) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 2059929 + ... + 2060055.

It is an arithmetic number, because the mean of its divisors is an integer number (3566112).

Almost surely, 2^261618984 is an apocalyptic number.

261618984 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 261618984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (427933440).

261618984 is an abundant number, since it is smaller than the sum of its proper divisors (594247896).

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

261618984 is a wasteful number, since it uses less digits than its factorization.

261618984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190 (or 160 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 261618984 is about 16174.6401505567. The cubic root of 261618984 is about 639.5724553327.

The spelling of 261618984 in words is "two hundred sixty-one million, six hundred eighteen thousand, nine hundred eighty-four".