61686240 has 192 divisors, whose sum is σ = 242403840. Its totient is φ = 12810240.

The previous prime is 61686239. The next prime is 61686259. The reversal of 61686240 is 4268616.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (33).

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, 36126 + ... + 37794.

It is an arithmetic number, because the mean of its divisors is an integer number (1262520).

Almost surely, 2^61686240 is an apocalyptic number.

61686240 is a gapful number since it is divisible by the number (60) 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 61686240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121201920).

61686240 is an abundant number, since it is smaller than the sum of its proper divisors (180717600).

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

61686240 is a wasteful number, since it uses less digits than its factorization.

61686240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1705 (or 1697 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 61686240 is about 7854.0588233091. The cubic root of 61686240 is about 395.1203820444.

The spelling of 61686240 in words is "sixty-one million, six hundred eighty-six thousand, two hundred forty".