191661197400 has 288 divisors, whose sum is σ = 653512860000. Its totient is φ = 50332170240.

The previous prime is 191661197333. The next prime is 191661197503. The reversal of 191661197400 is 4791166191.

191661197400 is a `hidden beast` number, since 1 + 91 + 66 + 11 + 97 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 42130326 + ... + 42134874.

It is an arithmetic number, because the mean of its divisors is an integer number (2269141875).

Almost surely, 2^191661197400 is an apocalyptic number.

191661197400 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 191661197400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (326756430000).

191661197400 is an abundant number, since it is smaller than the sum of its proper divisors (461851662600).

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

191661197400 is a wasteful number, since it uses less digits than its factorization.

191661197400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4923 (or 4911 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The spelling of 191661197400 in words is "one hundred ninety-one billion, six hundred sixty-one million, one hundred ninety-seven thousand, four hundred".