78669840 has 80 divisors (see below), whose sum is σ = 245359296. Its totient is φ = 20851200.

The previous prime is 78669839. The next prime is 78669853. The reversal of 78669840 is 4896687.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 78669840.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42535 + ... + 44345.

Almost surely, 2^78669840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78669840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122679648).

78669840 is an abundant number, since it is smaller than the sum of its proper divisors (166689456).

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

78669840 is a wasteful number, since it uses less digits than its factorization.

78669840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2008 (or 2002 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 48.

The square root of 78669840 is about 8869.6020203840. The cubic root of 78669840 is about 428.4854595817.

78669840 divided by its sum of digits (48) gives a triangular number (1638955 = T₁₈₁₀).

The spelling of 78669840 in words is "seventy-eight million, six hundred sixty-nine thousand, eight hundred forty".