121891971 has 8 divisors (see below), whose sum is σ = 166302400. Its totient is φ = 79371432.

The previous prime is 121891943. The next prime is 121891981. The reversal of 121891971 is 179198121.

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

It is not a de Polignac number, because 121891971 - 2⁹ = 121891459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121891981) 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, 472321 + ... + 472578.

It is an arithmetic number, because the mean of its divisors is an integer number (20787800).

Almost surely, 2^121891971 is an apocalyptic number.

121891971 is a deficient number, since it is larger than the sum of its proper divisors (44410429).

121891971 is an equidigital number, since it uses as much as digits as its factorization.

121891971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 944945.

The product of its digits is 9072, while the sum is 39.

The square root of 121891971 is about 11040.4696910956. The cubic root of 121891971 is about 495.8211327711.

The spelling of 121891971 in words is "one hundred twenty-one million, eight hundred ninety-one thousand, nine hundred seventy-one".