61299217728 has 336 divisors, whose sum is σ = 205562972160. Its totient is φ = 17103025152.

The previous prime is 61299217697. The next prime is 61299217769. The reversal of 61299217728 is 82771299216.

61299217728 is a `hidden beast` number, since 612 + 9 + 9 + 2 + 17 + 7 + 2 + 8 = 666.

61299217728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (336).

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 47 ways as a sum of consecutive naturals, for example, 39726525 + ... + 39728067.

It is an arithmetic number, because the mean of its divisors is an integer number (611794560).

Almost surely, 2^61299217728 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 61299217728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102781486080).

61299217728 is an abundant number, since it is smaller than the sum of its proper divisors (144263754432).

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

61299217728 is a wasteful number, since it uses less digits than its factorization.

61299217728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1794 (or 1781 counting only the distinct ones).

The product of its digits is 1524096, while the sum is 54.

The spelling of 61299217728 in words is "sixty-one billion, two hundred ninety-nine million, two hundred seventeen thousand, seven hundred twenty-eight".