78191389440 has 216 divisors, whose sum is σ = 270815021568. Its totient is φ = 20829388800.

The previous prime is 78191389391. The next prime is 78191389531. The reversal of 78191389440 is 4498319187.

78191389440 is a `hidden beast` number, since 7 + 8 + 191 + 3 + 8 + 9 + 440 = 666.

It is a super-2 number, since 2×78191389440² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13256572 + ... + 13262468.

It is an arithmetic number, because the mean of its divisors is an integer number (1253773248).

Almost surely, 2^78191389440 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 78191389440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135407510784).

78191389440 is an abundant number, since it is smaller than the sum of its proper divisors (192623632128).

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

78191389440 is a wasteful number, since it uses less digits than its factorization.

78191389440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7075 (or 7058 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The spelling of 78191389440 in words is "seventy-eight billion, one hundred ninety-one million, three hundred eighty-nine thousand, four hundred forty".