78678437421 has 16 divisors (see below), whose sum is σ = 109528983936. Its totient is φ = 50142730176.

The previous prime is 78678437419. The next prime is 78678437447. The reversal of 78678437421 is 12473487687.

It is not a de Polignac number, because 78678437421 - 2¹ = 78678437419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78678437021) 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, 209410 + ... + 448563.

It is an arithmetic number, because the mean of its divisors is an integer number (6845561496).

Almost surely, 2^78678437421 is an apocalyptic number.

It is an amenable number.

78678437421 is a deficient number, since it is larger than the sum of its proper divisors (30850546515).

78678437421 is a wasteful number, since it uses less digits than its factorization.

78678437421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659732.

The product of its digits is 12644352, while the sum is 57.

The spelling of 78678437421 in words is "seventy-eight billion, six hundred seventy-eight million, four hundred thirty-seven thousand, four hundred twenty-one".