61776669640 has 384 divisors, whose sum is σ = 172919577600. Its totient is φ = 19775508480.

The previous prime is 61776669637. The next prime is 61776669649. The reversal of 61776669640 is 4696667716.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (61776669649) 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 95 ways as a sum of consecutive naturals, for example, 234892149 + ... + 234892411.

It is an arithmetic number, because the mean of its divisors is an integer number (450311400).

Almost surely, 2^61776669640 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 61776669640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86459788800).

61776669640 is an abundant number, since it is smaller than the sum of its proper divisors (111142907960).

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

61776669640 is a wasteful number, since it uses less digits than its factorization.

61776669640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445 (or 434 counting only the distinct ones).

The product of its (nonzero) digits is 13716864, while the sum is 58.

The spelling of 61776669640 in words is "sixty-one billion, seven hundred seventy-six million, six hundred sixty-nine thousand, six hundred forty".