65681921088 has 448 divisors, whose sum is σ = 230028902400. Its totient is φ = 17983088640.

The previous prime is 65681921083. The next prime is 65681921111. The reversal of 65681921088 is 88012918656.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (448).

It is a super-2 number, since 2×65681921088² (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 not an unprimeable number, because it can be changed into a prime (65681921083) 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, 40871581 + ... + 40873187.

Almost surely, 2^65681921088 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 65681921088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115014451200).

65681921088 is an abundant number, since it is smaller than the sum of its proper divisors (164346981312).

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

65681921088 is a wasteful number, since it uses less digits than its factorization.

65681921088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1775 (or 1759 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 54.

The spelling of 65681921088 in words is "sixty-five billion, six hundred eighty-one million, nine hundred twenty-one thousand, eighty-eight".