78438331 has 4 divisors (see below), whose sum is σ = 78465672. Its totient is φ = 78410992.

The previous prime is 78438329. The next prime is 78438343. The reversal of 78438331 is 13383487.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13383487 = 13 ⋅1029499.

It is a cyclic number.

It is not a de Polignac number, because 78438331 - 2¹ = 78438329 is a prime.

It is a super-2 number, since 2×78438331² = 12305143540131122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78438431) 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, 8785 + ... + 15298.

It is an arithmetic number, because the mean of its divisors is an integer number (19616418).

Almost surely, 2^78438331 is an apocalyptic number.

78438331 is a deficient number, since it is larger than the sum of its proper divisors (27341).

78438331 is a wasteful number, since it uses less digits than its factorization.

78438331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27340.

The product of its digits is 48384, while the sum is 37.

The square root of 78438331 is about 8856.5417065579. The cubic root of 78438331 is about 428.0647320353.

The spelling of 78438331 in words is "seventy-eight million, four hundred thirty-eight thousand, three hundred thirty-one".