78684738 has 64 divisors (see below), whose sum is σ = 191393280. Its totient is φ = 21254400.

The previous prime is 78684737. The next prime is 78684761. The reversal of 78684738 is 83748687.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (78684731) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19473 + ... + 23163.

It is an arithmetic number, because the mean of its divisors is an integer number (2990520).

Almost surely, 2^78684738 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78684738, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95696640).

78684738 is an abundant number, since it is smaller than the sum of its proper divisors (112708542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78684738 is a wasteful number, since it uses less digits than its factorization.

78684738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3743.

The product of its digits is 1806336, while the sum is 51.

The square root of 78684738 is about 8870.4418153776. The cubic root of 78684738 is about 428.5125058358.

It can be divided in two parts, 786847 and 38, that added together give a triangular number (786885 = T₁₂₅₄).

The spelling of 78684738 in words is "seventy-eight million, six hundred eighty-four thousand, seven hundred thirty-eight".