78073891 has 16 divisors (see below), whose sum is σ = 93542400. Its totient is φ = 63711648.

The previous prime is 78073889. The next prime is 78073901. The reversal of 78073891 is 19837087.

It is not a de Polignac number, because 78073891 - 2¹ = 78073889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78073871) 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 15 ways as a sum of consecutive naturals, for example, 37465 + ... + 39493.

It is an arithmetic number, because the mean of its divisors is an integer number (5846400).

Almost surely, 2^78073891 is an apocalyptic number.

78073891 is a deficient number, since it is larger than the sum of its proper divisors (15468509).

78073891 is a wasteful number, since it uses less digits than its factorization.

78073891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2298.

The product of its (nonzero) digits is 84672, while the sum is 43.

The square root of 78073891 is about 8835.9431301927. The cubic root of 78073891 is about 427.4007448287.

The spelling of 78073891 in words is "seventy-eight million, seventy-three thousand, eight hundred ninety-one".