61718228640 has 576 divisors, whose sum is σ = 226643743872. Its totient is φ = 15850598400.

The previous prime is 61718228623. The next prime is 61718228653. The reversal of 61718228640 is 4682281716.

61718228640 is a `hidden beast` number, since 617 + 1 + 8 + 2 + 28 + 6 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 125698795 + ... + 125699285.

It is an arithmetic number, because the mean of its divisors is an integer number (393478722).

Almost surely, 2^61718228640 is an apocalyptic number.

61718228640 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 61718228640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113321871936).

61718228640 is an abundant number, since it is smaller than the sum of its proper divisors (164925515232).

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

61718228640 is a wasteful number, since it uses less digits than its factorization.

61718228640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635 (or 615 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 61718228640 in words is "sixty-one billion, seven hundred eighteen million, two hundred twenty-eight thousand, six hundred forty".