78638137 has 8 divisors (see below), whose sum is σ = 79433352. Its totient is φ = 77846400.

The previous prime is 78638117. The next prime is 78638143. The reversal of 78638137 is 73183687.

It can be written as a sum of positive squares in 4 ways, for example, as 15848361 + 62789776 = 3981^2 + 7924^2 .

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 78638137 - 2¹⁵ = 78605369 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78638093 and 78638102.

It is not an unprimeable number, because it can be changed into a prime (78638117) 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, 73587 + ... + 74647.

It is an arithmetic number, because the mean of its divisors is an integer number (9929169).

Almost surely, 2^78638137 is an apocalyptic number.

It is an amenable number.

78638137 is a deficient number, since it is larger than the sum of its proper divisors (795215).

78638137 is a wasteful number, since it uses less digits than its factorization.

78638137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1739.

The product of its digits is 169344, while the sum is 43.

The square root of 78638137 is about 8867.8146687896. The cubic root of 78638137 is about 428.4278936847.

The spelling of 78638137 in words is "seventy-eight million, six hundred thirty-eight thousand, one hundred thirty-seven".