78091990 has 8 divisors (see below), whose sum is σ = 140565600. Its totient is φ = 31236792.

The previous prime is 78091973. The next prime is 78091991. The reversal of 78091990 is 9919087.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78091991) 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, 3904590 + ... + 3904609.

It is an arithmetic number, because the mean of its divisors is an integer number (17570700).

Almost surely, 2^78091990 is an apocalyptic number.

78091990 is a deficient number, since it is larger than the sum of its proper divisors (62473610).

78091990 is a wasteful number, since it uses less digits than its factorization.

78091990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7809206.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 78091990 is about 8836.9672399529. The cubic root of 78091990 is about 427.4337687941.

The spelling of 78091990 in words is "seventy-eight million, ninety-one thousand, nine hundred ninety".