261228240 has 400 divisors, whose sum is σ = 1119178368. Its totient is φ = 54991872.

The previous prime is 261228199. The next prime is 261228257. The reversal of 261228240 is 42822162.

It is a happy number.

261228240 is a `hidden beast` number, since 2 + 612 + 2 + 8 + 2 + 40 = 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 79 ways as a sum of consecutive naturals, for example, 589459 + ... + 589901.

Almost surely, 2^261228240 is an apocalyptic number.

261228240 is a gapful number since it is divisible by the number (20) 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 261228240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (559589184).

261228240 is an abundant number, since it is smaller than the sum of its proper divisors (857950128).

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

261228240 is a wasteful number, since it uses less digits than its factorization.

261228240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488 (or 473 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 261228240 is about 16162.5567284387. The cubic root of 261228240 is about 639.2538831134.

The spelling of 261228240 in words is "two hundred sixty-one million, two hundred twenty-eight thousand, two hundred forty".