191783661740 has 72 divisors (see below), whose sum is σ = 443094926400. Its totient is φ = 69675316480.

The previous prime is 191783661709. The next prime is 191783661743. The reversal of 191783661740 is 47166387191.

It is not an unprimeable number, because it can be changed into a prime (191783661743) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2633336 + ... + 2705184.

It is an arithmetic number, because the mean of its divisors is an integer number (6154096200).

Almost surely, 2^191783661740 is an apocalyptic number.

191783661740 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 191783661740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221547463200).

191783661740 is an abundant number, since it is smaller than the sum of its proper divisors (251311264660).

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

191783661740 is a wasteful number, since it uses less digits than its factorization.

191783661740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72983 (or 72970 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 53.

The spelling of 191783661740 in words is "one hundred ninety-one billion, seven hundred eighty-three million, six hundred sixty-one thousand, seven hundred forty".