78138499 has 8 divisors (see below), whose sum is σ = 82159920. Its totient is φ = 74205600.

The previous prime is 78138493. The next prime is 78138509. The reversal of 78138499 is 99483187.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 78138499 - 2⁷ = 78138371 is a prime.

It is a super-2 number, since 2×78138499² = 12211250051946002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78138493) 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, 20317 + ... + 23854.

It is an arithmetic number, because the mean of its divisors is an integer number (10269990).

Almost surely, 2^78138499 is an apocalyptic number.

78138499 is a deficient number, since it is larger than the sum of its proper divisors (4021421).

78138499 is a wasteful number, since it uses less digits than its factorization.

78138499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44261.

The product of its digits is 435456, while the sum is 49.

The square root of 78138499 is about 8839.5983506039. The cubic root of 78138499 is about 427.5186070809.

The spelling of 78138499 in words is "seventy-eight million, one hundred thirty-eight thousand, four hundred ninety-nine".