78391006 has 4 divisors (see below), whose sum is σ = 117586512. Its totient is φ = 39195502.

The previous prime is 78390997. The next prime is 78391007. The reversal of 78391006 is 60019387.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×78391006² = 12290299643384072, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78391007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19597750 + ... + 19597753.

It is an arithmetic number, because the mean of its divisors is an integer number (29396628).

Almost surely, 2^78391006 is an apocalyptic number.

78391006 is a deficient number, since it is larger than the sum of its proper divisors (39195506).

78391006 is a wasteful number, since it uses less digits than its factorization.

78391006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39195505.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 78391006 is about 8853.8695495247. The cubic root of 78391006 is about 427.9786251590.

The spelling of 78391006 in words is "seventy-eight million, three hundred ninety-one thousand, six".