78440881 has 4 divisors (see below), whose sum is σ = 80971264. Its totient is φ = 75910500.

The previous prime is 78440867. The next prime is 78440903. The reversal of 78440881 is 18804487.

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.

It is a cyclic number.

It is not a de Polignac number, because 78440881 - 2⁵ = 78440849 is a prime.

It is a super-2 number, since 2×78440881² = 12305943624112322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78440801) 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, 1265145 + ... + 1265206.

It is an arithmetic number, because the mean of its divisors is an integer number (20242816).

Almost surely, 2^78440881 is an apocalyptic number.

It is an amenable number.

78440881 is a deficient number, since it is larger than the sum of its proper divisors (2530383).

78440881 is a wasteful number, since it uses less digits than its factorization.

78440881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2530382.

The product of its (nonzero) digits is 57344, while the sum is 40.

The square root of 78440881 is about 8856.6856667717. The cubic root of 78440881 is about 428.0693707250.

The spelling of 78440881 in words is "seventy-eight million, four hundred forty thousand, eight hundred eighty-one".