261242388 has 72 divisors (see below), whose sum is σ = 744502080. Its totient is φ = 79160400.

The previous prime is 261242369. The next prime is 261242431. The reversal of 261242388 is 883242162.

261242388 is a `hidden beast` number, since 2 + 612 + 4 + 2 + 38 + 8 = 666.

261242388 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×261242388³ (a number of 26 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3073 + ... + 23063.

Almost surely, 2^261242388 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261242388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (372251040).

261242388 is an abundant number, since it is smaller than the sum of its proper divisors (483259692).

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

261242388 is a wasteful number, since it uses less digits than its factorization.

261242388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20026 (or 20007 counting only the distinct ones).

The product of its digits is 36864, while the sum is 36.

The square root of 261242388 is about 16162.9944007910. The cubic root of 261242388 is about 639.2654234694.

The spelling of 261242388 in words is "two hundred sixty-one million, two hundred forty-two thousand, three hundred eighty-eight".