78369591 has 4 divisors (see below), whose sum is σ = 104492792. Its totient is φ = 52246392.

The previous prime is 78369553. The next prime is 78369631. The reversal of 78369591 is 19596387.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19596387 = 3 ⋅6532129.

It is not a de Polignac number, because 78369591 - 2⁶ = 78369527 is a prime.

It is a super-2 number, since 2×78369591² = 12283585587014562, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78369591.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78369391) 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, 13061596 + ... + 13061601.

It is an arithmetic number, because the mean of its divisors is an integer number (26123198).

Almost surely, 2^78369591 is an apocalyptic number.

78369591 is a deficient number, since it is larger than the sum of its proper divisors (26123201).

78369591 is a wasteful number, since it uses less digits than its factorization.

78369591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26123200.

The product of its digits is 408240, while the sum is 48.

The square root of 78369591 is about 8852.6601086905. The cubic root of 78369591 is about 427.9396496122.

The spelling of 78369591 in words is "seventy-eight million, three hundred sixty-nine thousand, five hundred ninety-one".