261438624 has 192 divisors, whose sum is σ = 808980480. Its totient is φ = 82010880.

The previous prime is 261438577. The next prime is 261438637. The reversal of 261438624 is 426834162.

261438624 is a `hidden beast` number, since 2 + 614 + 38 + 6 + 2 + 4 = 666.

261438624 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

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

It is a congruent number.

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, 1151599 + ... + 1151825.

It is an arithmetic number, because the mean of its divisors is an integer number (4213440).

Almost surely, 2^261438624 is an apocalyptic number.

261438624 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 261438624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (404490240).

261438624 is an abundant number, since it is smaller than the sum of its proper divisors (547541856).

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

261438624 is a wasteful number, since it uses less digits than its factorization.

261438624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320 (or 306 counting only the distinct ones).

The product of its digits is 55296, while the sum is 36.

The square root of 261438624 is about 16169.0637947903. The cubic root of 261438624 is about 639.4254478990.

The spelling of 261438624 in words is "two hundred sixty-one million, four hundred thirty-eight thousand, six hundred twenty-four".