140191991 has 4 divisors (see below), whose sum is σ = 141031632. Its totient is φ = 139352352.

The previous prime is 140191967. The next prime is 140191993. The reversal of 140191991 is 199191041.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-140191991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (140191993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 419570 + ... + 419903.

It is an arithmetic number, because the mean of its divisors is an integer number (35257908).

Almost surely, 2^140191991 is an apocalyptic number.

140191991 is a deficient number, since it is larger than the sum of its proper divisors (839641).

140191991 is an equidigital number, since it uses as much as digits as its factorization.

140191991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 839640.

The product of its (nonzero) digits is 2916, while the sum is 35.

The square root of 140191991 is about 11840.2698871267. The cubic root of 140191991 is about 519.4866617975.

The spelling of 140191991 in words is "one hundred forty million, one hundred ninety-one thousand, nine hundred ninety-one".