191656640 has 168 divisors, whose sum is σ = 562904640. Its totient is φ = 61759488.

The previous prime is 191656627. The next prime is 191656687. The reversal of 191656640 is 46656191.

It is a junction number, because it is equal to n+sod(n) for n = 191656594 and 191656603.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 266201 + ... + 266919.

Almost surely, 2^191656640 is an apocalyptic number.

191656640 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 191656640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (281452320).

191656640 is an abundant number, since it is smaller than the sum of its proper divisors (371248000).

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

191656640 is a wasteful number, since it uses less digits than its factorization.

191656640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 767 (or 750 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 191656640 is about 13844.0109794813. The cubic root of 191656640 is about 576.5557265210. Note that the first 3 decimals are identical.

The spelling of 191656640 in words is "one hundred ninety-one million, six hundred fifty-six thousand, six hundred forty".