78051891 has 16 divisors (see below), whose sum is σ = 105778080. Its totient is φ = 51187200.

The previous prime is 78051889. The next prime is 78051901. The reversal of 78051891 is 19815087.

It is not a de Polignac number, because 78051891 - 2¹ = 78051889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78051821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51675 + ... + 53163.

It is an arithmetic number, because the mean of its divisors is an integer number (6611130).

Almost surely, 2^78051891 is an apocalyptic number.

78051891 is a deficient number, since it is larger than the sum of its proper divisors (27726189).

78051891 is a wasteful number, since it uses less digits than its factorization.

78051891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766.

The product of its (nonzero) digits is 20160, while the sum is 39.

The square root of 78051891 is about 8834.6981272707. The cubic root of 78051891 is about 427.3605961115.

The spelling of 78051891 in words is "seventy-eight million, fifty-one thousand, eight hundred ninety-one".