78289121 has 4 divisors (see below), whose sum is σ = 78807744. Its totient is φ = 77770500.

The previous prime is 78289103. The next prime is 78289153. The reversal of 78289121 is 12198287.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12198287 = 2657 ⋅4591.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78289121 is a prime.

It is a super-2 number, since 2×78289121² = 12258372933905282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78289021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 259085 + ... + 259386.

It is an arithmetic number, because the mean of its divisors is an integer number (19701936).

Almost surely, 2^78289121 is an apocalyptic number.

It is an amenable number.

78289121 is a deficient number, since it is larger than the sum of its proper divisors (518623).

78289121 is a wasteful number, since it uses less digits than its factorization.

78289121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518622.

The product of its digits is 16128, while the sum is 38.

The square root of 78289121 is about 8848.1139798264. The cubic root of 78289121 is about 427.7931297852.

The spelling of 78289121 in words is "seventy-eight million, two hundred eighty-nine thousand, one hundred twenty-one".