261405144 has 480 divisors, whose sum is σ = 1020349440. Its totient is φ = 60652800.

The previous prime is 261405091. The next prime is 261405167. The reversal of 261405144 is 441504162.

261405144 is a `hidden beast` number, since 2 + 6 + 140 + 514 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 8432409 + ... + 8432439.

It is an arithmetic number, because the mean of its divisors is an integer number (2125728).

Almost surely, 2^261405144 is an apocalyptic number.

261405144 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 261405144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (510174720).

261405144 is an abundant number, since it is smaller than the sum of its proper divisors (758944296).

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

261405144 is a wasteful number, since it uses less digits than its factorization.

261405144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 261405144 is about 16168.0284512367. The cubic root of 261405144 is about 639.3981516543.

The spelling of 261405144 in words is "two hundred sixty-one million, four hundred five thousand, one hundred forty-four".