61491579968 has 112 divisors (see below), whose sum is σ = 152644230144. Its totient is φ = 23927408640.

The previous prime is 61491579967. The next prime is 61491579977. The reversal of 61491579968 is 86997519416.

It is a tau number, because it is divible by the number of its divisors (112).

It is not an unprimeable number, because it can be changed into a prime (61491579967) 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, 268721 + ... + 441807.

It is an arithmetic number, because the mean of its divisors is an integer number (1362894912).

Almost surely, 2^61491579968 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 61491579968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76322115072).

61491579968 is an abundant number, since it is smaller than the sum of its proper divisors (91152650176).

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

61491579968 is a wasteful number, since it uses less digits than its factorization.

61491579968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173180 (or 173170 counting only the distinct ones).

The product of its digits is 29393280, while the sum is 65.

The spelling of 61491579968 in words is "sixty-one billion, four hundred ninety-one million, five hundred seventy-nine thousand, nine hundred sixty-eight".