121991623 has 8 divisors (see below), whose sum is σ = 131518800. Its totient is φ = 112484928.

The previous prime is 121991621. The next prime is 121991671. The reversal of 121991623 is 326199121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 121991623 - 2¹ = 121991621 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 (121991621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8643 + ... + 17851.

It is an arithmetic number, because the mean of its divisors is an integer number (16439850).

Almost surely, 2^121991623 is an apocalyptic number.

121991623 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

121991623 is a deficient number, since it is larger than the sum of its proper divisors (9527177).

121991623 is a wasteful number, since it uses less digits than its factorization.

121991623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10241.

The product of its digits is 5832, while the sum is 34.

The square root of 121991623 is about 11044.9818017052. The cubic root of 121991623 is about 495.9562144296.

The spelling of 121991623 in words is "one hundred twenty-one million, nine hundred ninety-one thousand, six hundred twenty-three".