78139049 has 4 divisors (see below), whose sum is σ = 78575760. Its totient is φ = 77702340.

The previous prime is 78139043. The next prime is 78139067. The reversal of 78139049 is 94093187.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78139049 - 2²⁰ = 77090473 is a prime.

It is a super-2 number, since 2×78139049² = 12211421957248802, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78138997 and 78139015.

It is not an unprimeable number, because it can be changed into a prime (78139043) 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, 218087 + ... + 218444.

It is an arithmetic number, because the mean of its divisors is an integer number (19643940).

Almost surely, 2^78139049 is an apocalyptic number.

It is an amenable number.

78139049 is a deficient number, since it is larger than the sum of its proper divisors (436711).

78139049 is a wasteful number, since it uses less digits than its factorization.

78139049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436710.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 78139049 is about 8839.6294605600. The cubic root of 78139049 is about 427.5196101488.

The spelling of 78139049 in words is "seventy-eight million, one hundred thirty-nine thousand, forty-nine".