121991953 has 8 divisors (see below), whose sum is σ = 123568200. Its totient is φ = 120422400.

The previous prime is 121991939. The next prime is 121991957. The reversal of 121991953 is 359199121.

It can be written as a sum of positive squares in 4 ways, for example, as 21049744 + 100942209 = 4588^2 + 10047^2 .

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 121991953 - 2⁵ = 121991921 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is not an unprimeable number, because it can be changed into a prime (121991957) 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 7 ways as a sum of consecutive naturals, for example, 42153 + ... + 44953.

It is an arithmetic number, because the mean of its divisors is an integer number (15446025).

Almost surely, 2^121991953 is an apocalyptic number.

It is an amenable number.

121991953 is a deficient number, since it is larger than the sum of its proper divisors (1576247).

121991953 is an equidigital number, since it uses as much as digits as its factorization.

121991953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3347.

The product of its digits is 21870, while the sum is 40.

The square root of 121991953 is about 11044.9967406061. The cubic root of 121991953 is about 495.9566616335.

The spelling of 121991953 in words is "one hundred twenty-one million, nine hundred ninety-one thousand, nine hundred fifty-three".