78291121 has 8 divisors (see below), whose sum is σ = 79725800. Its totient is φ = 76861440.

The previous prime is 78291071. The next prime is 78291127. The reversal of 78291121 is 12119287.

It can be written as a sum of positive squares in 4 ways, for example, as 216225 + 78074896 = 465^2 + 8836^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 78291121 - 2¹³ = 78282929 is a prime.

It is a super-2 number, since 2×78291121² = 12258999254873282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78291127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46075 + ... + 47743.

It is an arithmetic number, because the mean of its divisors is an integer number (9965725).

Almost surely, 2^78291121 is an apocalyptic number.

It is an amenable number.

78291121 is a deficient number, since it is larger than the sum of its proper divisors (1434679).

78291121 is a wasteful number, since it uses less digits than its factorization.

78291121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2499.

The product of its digits is 2016, while the sum is 31.

The square root of 78291121 is about 8848.2269975402. The cubic root of 78291121 is about 427.7967726028.

The spelling of 78291121 in words is "seventy-eight million, two hundred ninety-one thousand, one hundred twenty-one".