65978115840 has 1728 divisors, whose sum is σ = 304952699520. Its totient is φ = 13544423424.

The previous prime is 65978115823. The next prime is 65978115851. The reversal of 65978115840 is 4851187956.

It is a happy number.

65978115840 is a `hidden beast` number, since 6 + 59 + 7 + 8 + 1 + 1 + 584 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a super-2 number, since 2×65978115840² (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 congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1783192302 + ... + 1783192338.

Almost surely, 2^65978115840 is an apocalyptic number.

65978115840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65978115840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152476349760).

65978115840 is an abundant number, since it is smaller than the sum of its proper divisors (238974583680).

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

65978115840 is an equidigital number, since it uses as much as digits as its factorization.

65978115840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 2419200, while the sum is 54.

The spelling of 65978115840 in words is "sixty-five billion, nine hundred seventy-eight million, one hundred fifteen thousand, eight hundred forty".