191979944640 has 896 divisors, whose sum is σ = 807738531840. Its totient is φ = 42378854400.

The previous prime is 191979944633. The next prime is 191979944641. The reversal of 191979944640 is 46449979191.

191979944640 is a `hidden beast` number, since 1 + 9 + 19 + 79 + 94 + 464 + 0 = 666.

191979944640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (191979944641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 50084164 + ... + 50087996.

Almost surely, 2^191979944640 is an apocalyptic number.

191979944640 is a gapful number since it is divisible by the number (10) 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 191979944640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (403869265920).

191979944640 is an abundant number, since it is smaller than the sum of its proper divisors (615758587200).

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

191979944640 is a wasteful number, since it uses less digits than its factorization.

191979944640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3918 (or 3902 counting only the distinct ones).

The product of its (nonzero) digits is 17635968, while the sum is 63.

The spelling of 191979944640 in words is "one hundred ninety-one billion, nine hundred seventy-nine million, nine hundred forty-four thousand, six hundred forty".