61642564144 has 80 divisors (see below), whose sum is σ = 140504632128. Its totient is φ = 25652330496.

The previous prime is 61642564133. The next prime is 61642564147. The reversal of 61642564144 is 44146524616.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 61642564144.

It is not an unprimeable number, because it can be changed into a prime (61642564147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 522264 + ... + 629320.

Almost surely, 2^61642564144 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 61642564144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (70252316064).

61642564144 is an abundant number, since it is smaller than the sum of its proper divisors (78862067984).

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

61642564144 is a wasteful number, since it uses less digits than its factorization.

61642564144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107222 (or 107216 counting only the distinct ones).

The product of its digits is 552960, while the sum is 43.

The spelling of 61642564144 in words is "sixty-one billion, six hundred forty-two million, five hundred sixty-four thousand, one hundred forty-four".