121978478 has 4 divisors (see below), whose sum is σ = 182967720. Its totient is φ = 60989238.

The previous prime is 121978469. The next prime is 121978501. The reversal of 121978478 is 874879121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 874879121 = 6983 ⋅125287.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30494618 + ... + 30494621.

It is an arithmetic number, because the mean of its divisors is an integer number (45741930).

Almost surely, 2^121978478 is an apocalyptic number.

121978478 is a deficient number, since it is larger than the sum of its proper divisors (60989242).

121978478 is an equidigital number, since it uses as much as digits as its factorization.

121978478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60989241.

The product of its digits is 225792, while the sum is 47.

The square root of 121978478 is about 11044.3867190533. The cubic root of 121978478 is about 495.9384001501.

It can be divided in two parts, 1219 and 78478, that added together give a palindrome (79697).

The spelling of 121978478 in words is "one hundred twenty-one million, nine hundred seventy-eight thousand, four hundred seventy-eight".