78066591 has 8 divisors (see below), whose sum is σ = 105642624. Its totient is φ = 51267480.

The previous prime is 78066589. The next prime is 78066607. The reversal of 78066591 is 19566087.

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

It is not a de Polignac number, because 78066591 - 2¹ = 78066589 is a prime.

It is a super-2 number, since 2×78066591² = 12188785260722562, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78066511) 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, 193995 + ... + 194396.

It is an arithmetic number, because the mean of its divisors is an integer number (13205328).

Almost surely, 2^78066591 is an apocalyptic number.

78066591 is a deficient number, since it is larger than the sum of its proper divisors (27576033).

78066591 is a wasteful number, since it uses less digits than its factorization.

78066591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388461.

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 78066591 is about 8835.5300350347. The cubic root of 78066591 is about 427.3874235906.

The spelling of 78066591 in words is "seventy-eight million, sixty-six thousand, five hundred ninety-one".