78384639 has 16 divisors (see below), whose sum is σ = 106513920. Its totient is φ = 51263520.

The previous prime is 78384617. The next prime is 78384641. The reversal of 78384639 is 93648387.

It is not a de Polignac number, because 78384639 - 2¹² = 78380543 is a prime.

It is a super-2 number, since 2×78384639² = 12288303262320642, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78384659) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47974 + ... + 49580.

It is an arithmetic number, because the mean of its divisors is an integer number (6657120).

Almost surely, 2^78384639 is an apocalyptic number.

78384639 is a deficient number, since it is larger than the sum of its proper divisors (28129281).

78384639 is a wasteful number, since it uses less digits than its factorization.

78384639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1910.

The product of its digits is 870912, while the sum is 48.

The square root of 78384639 is about 8853.5099819224. The cubic root of 78384639 is about 427.9670378872.

The spelling of 78384639 in words is "seventy-eight million, three hundred eighty-four thousand, six hundred thirty-nine".