61638660 has 144 divisors (see below), whose sum is σ = 200491200. Its totient is φ = 15282432.

The previous prime is 61638649. The next prime is 61638677. The reversal of 61638660 is 6683616.

61638660 is a `hidden beast` number, since 616 + 38 + 6 + 6 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 229006 + ... + 229274.

It is an arithmetic number, because the mean of its divisors is an integer number (1392300).

Almost surely, 2^61638660 is an apocalyptic number.

61638660 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 61638660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100245600).

61638660 is an abundant number, since it is smaller than the sum of its proper divisors (138852540).

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

61638660 is a wasteful number, since it uses less digits than its factorization.

61638660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 61638660 is about 7851.0292318906. The cubic root of 61638660 is about 395.0187674681.

The spelling of 61638660 in words is "sixty-one million, six hundred thirty-eight thousand, six hundred sixty".