61611978912 has 96 divisors (see below), whose sum is σ = 176733627840. Its totient is φ = 18638622720.

The previous prime is 61611978871. The next prime is 61611978919. The reversal of 61611978912 is 21987911616.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (61611978919) 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, 577014 + ... + 675402.

It is an arithmetic number, because the mean of its divisors is an integer number (1840975290).

Almost surely, 2^61611978912 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 61611978912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88366813920).

61611978912 is an abundant number, since it is smaller than the sum of its proper divisors (115121648928).

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

61611978912 is a wasteful number, since it uses less digits than its factorization.

61611978912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99006 (or 98998 counting only the distinct ones).

The product of its digits is 326592, while the sum is 51.

The spelling of 61611978912 in words is "sixty-one billion, six hundred eleven million, nine hundred seventy-eight thousand, nine hundred twelve".