121911921 has 6 divisors (see below), whose sum is σ = 176095010. Its totient is φ = 81274608.

The previous prime is 121911919. The next prime is 121911973. The reversal of 121911921 is 129119121.

It can be written as a sum of positive squares in only one way, i.e., 87160896 + 34751025 = 9336^2 + 5895^2 .

It is not a de Polignac number, because 121911921 - 2¹ = 121911919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121911721) 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 5 ways as a sum of consecutive naturals, for example, 6772876 + ... + 6772893.

Almost surely, 2^121911921 is an apocalyptic number.

It is an amenable number.

121911921 is a deficient number, since it is larger than the sum of its proper divisors (54183089).

121911921 is a wasteful number, since it uses less digits than its factorization.

121911921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13545775 (or 13545772 counting only the distinct ones).

The product of its digits is 324, while the sum is 27.

The square root of 121911921 is about 11041.3731483000. The cubic root of 121911921 is about 495.8481815638.

The spelling of 121911921 in words is "one hundred twenty-one million, nine hundred eleven thousand, nine hundred twenty-one".