26391978 has 48 divisors (see below), whose sum is σ = 58833216. Its totient is φ = 8547840.

The previous prime is 26391947. The next prime is 26391983. The reversal of 26391978 is 87919362.

26391978 is a `hidden beast` number, since 2 + 639 + 1 + 9 + 7 + 8 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136650 + ... + 136842.

It is an arithmetic number, because the mean of its divisors is an integer number (1225692).

Almost surely, 2^26391978 is an apocalyptic number.

26391978 is an abundant number, since it is smaller than the sum of its proper divisors (32441238).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

26391978 is a wasteful number, since it uses less digits than its factorization.

26391978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379 (or 376 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 26391978 is about 5137.3123323388. The cubic root of 26391978 is about 297.7309479442.

The spelling of 26391978 in words is "twenty-six million, three hundred ninety-one thousand, nine hundred seventy-eight".