120617991 has 20 divisors (see below), whose sum is σ = 194044312. Its totient is φ = 74225808.

The previous prime is 120617971. The next prime is 120617999. The reversal of 120617991 is 199716021.

It is not a de Polignac number, because 120617991 - 2⁶ = 120617927 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (120617999) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 56221 + ... + 58326.

Almost surely, 2^120617991 is an apocalyptic number.

120617991 is a deficient number, since it is larger than the sum of its proper divisors (73426321).

120617991 is a wasteful number, since it uses less digits than its factorization.

120617991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114572 (or 114563 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 36.

The square root of 120617991 is about 10982.6222278653. The cubic root of 120617991 is about 494.0876859759.

The spelling of 120617991 in words is "one hundred twenty million, six hundred seventeen thousand, nine hundred ninety-one".