78055391 has 8 divisors (see below), whose sum is σ = 79847424. Its totient is φ = 76268920.

The previous prime is 78055301. The next prime is 78055409. The reversal of 78055391 is 19355087.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-78055391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78055301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41906 + ... + 43728.

It is an arithmetic number, because the mean of its divisors is an integer number (9980928).

Almost surely, 2^78055391 is an apocalyptic number.

78055391 is a deficient number, since it is larger than the sum of its proper divisors (1792033).

78055391 is a wasteful number, since it uses less digits than its factorization.

78055391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2781.

The product of its (nonzero) digits is 37800, while the sum is 38.

The square root of 78055391 is about 8834.8962076529. The cubic root of 78055391 is about 427.3669839120.

The spelling of 78055391 in words is "seventy-eight million, fifty-five thousand, three hundred ninety-one".