61645257684 has 192 divisors, whose sum is σ = 166634496000. Its totient is φ = 19942897248.

The previous prime is 61645257679. The next prime is 61645257733. The reversal of 61645257684 is 48675254616.

61645257684 is a `hidden beast` number, since 6 + 1 + 64 + 5 + 2 + 576 + 8 + 4 = 666.

It is a super-2 number, since 2×61645257684² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 61645257684.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42838237 + ... + 42839675.

It is an arithmetic number, because the mean of its divisors is an integer number (867888000).

Almost surely, 2^61645257684 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 61645257684, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83317248000).

61645257684 is an abundant number, since it is smaller than the sum of its proper divisors (104989238316).

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

61645257684 is a wasteful number, since it uses less digits than its factorization.

61645257684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1606 (or 1586 counting only the distinct ones).

The product of its digits is 9676800, while the sum is 54.

The spelling of 61645257684 in words is "sixty-one billion, six hundred forty-five million, two hundred fifty-seven thousand, six hundred eighty-four".