61328978864 has 80 divisors (see below), whose sum is σ = 127520632800. Its totient is φ = 28471971840.

The previous prime is 61328978857. The next prime is 61328978869. The reversal of 61328978864 is 46887982316.

It is a super-2 number, since 2×61328978864² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 61328978797 and 61328978806.

It is not an unprimeable number, because it can be changed into a prime (61328978869) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6159362 + ... + 6169310.

It is an arithmetic number, because the mean of its divisors is an integer number (1594007910).

Almost surely, 2^61328978864 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 61328978864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63760316400).

61328978864 is an abundant number, since it is smaller than the sum of its proper divisors (66191653936).

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

61328978864 is a wasteful number, since it uses less digits than its factorization.

61328978864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10278 (or 10272 counting only the distinct ones).

The product of its digits is 27869184, while the sum is 62.

The spelling of 61328978864 in words is "sixty-one billion, three hundred twenty-eight million, nine hundred seventy-eight thousand, eight hundred sixty-four".