121917978954 has 28 divisors (see below), whose sum is σ = 274190025906. Its totient is φ = 40639325832.

The previous prime is 121917978953. The next prime is 121917978967. The reversal of 121917978954 is 459879719121.

It can be written as a sum of positive squares in only one way, i.e., 78863803929 + 43054175025 = 280827^2 + 207495^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 121917978891 and 121917978900.

It is not an unprimeable number, because it can be changed into a prime (121917978953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 41808549 + ... + 41811464.

Almost surely, 2^121917978954 is an apocalyptic number.

121917978954 is an abundant number, since it is smaller than the sum of its proper divisors (152272046952).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121917978954 is an frugal number, since it uses more digits than its factorization.

121917978954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83620033 (or 83620018 counting only the distinct ones).

The product of its digits is 11430720, while the sum is 63.

The spelling of 121917978954 in words is "one hundred twenty-one billion, nine hundred seventeen million, nine hundred seventy-eight thousand, nine hundred fifty-four".