61719665384 has 72 divisors (see below), whose sum is σ = 132480885810. Its totient is φ = 26791643136.

The previous prime is 61719665369. The next prime is 61719665387. The reversal of 61719665384 is 48356691716.

It can be written as a sum of positive squares in 9 ways, for example, as 34980220900 + 26739444484 = 187030^2 + 163522^2 .

It is a super-2 number, since 2×61719665384² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61719665387) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 43069532 + ... + 43070964.

Almost surely, 2^61719665384 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 61719665384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66240442905).

61719665384 is an abundant number, since it is smaller than the sum of its proper divisors (70761220426).

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

61719665384 is a wasteful number, since it uses less digits than its factorization.

61719665384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2919 (or 1465 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 56.

The spelling of 61719665384 in words is "sixty-one billion, seven hundred nineteen million, six hundred sixty-five thousand, three hundred eighty-four".