61644684089898 has 128 divisors (see below), whose sum is σ = 168621229002240. Its totient is φ = 16255973099520.

The previous prime is 61644684089893. The next prime is 61644684089917. The reversal of 61644684089898 is 89898048644616.

61644684089898 is a `hidden beast` number, since 6 + 1 + 6 + 446 + 8 + 4 + 0 + 89 + 8 + 98 = 666.

It is a super-2 number, since 2×61644684089898² (a number of 28 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61644684089893) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 40115578 + ... + 41623898.

It is an arithmetic number, because the mean of its divisors is an integer number (1317353351580).

Almost surely, 2^{61644684089898} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61644684089898, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84310614501120).

61644684089898 is an abundant number, since it is smaller than the sum of its proper divisors (106976544912342).

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

61644684089898 is a wasteful number, since it uses less digits than its factorization.

61644684089898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1516669 (or 1516663 counting only the distinct ones).

The product of its (nonzero) digits is 4586471424, while the sum is 81.

The spelling of 61644684089898 in words is "sixty-one trillion, six hundred forty-four billion, six hundred eighty-four million, eighty-nine thousand, eight hundred ninety-eight".