191901640 has 128 divisors (see below), whose sum is σ = 513216000. Its totient is φ = 64538880.

The previous prime is 191901631. The next prime is 191901667. The reversal of 191901640 is 46109191.

191901640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 974022 + ... + 974218.

It is an arithmetic number, because the mean of its divisors is an integer number (4009500).

Almost surely, 2^191901640 is an apocalyptic number.

191901640 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 191901640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (256608000).

191901640 is an abundant number, since it is smaller than the sum of its proper divisors (321314360).

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

191901640 is a wasteful number, since it uses less digits than its factorization.

191901640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300 (or 282 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 191901640 is about 13852.8567450905. The cubic root of 191901640 is about 576.8012976374.

The spelling of 191901640 in words is "one hundred ninety-one million, nine hundred one thousand, six hundred forty".