78787664 has 40 divisors (see below), whose sum is σ = 158743560. Its totient is φ = 37836288.

The previous prime is 78787663. The next prime is 78787669. The reversal of 78787664 is 46678787.

It can be written as a sum of positive squares in 4 ways, for example, as 1488400 + 77299264 = 1220^2 + 8792^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78787663) 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, 128222 + ... + 128834.

It is an arithmetic number, because the mean of its divisors is an integer number (3968589).

Almost surely, 2^78787664 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 78787664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (79371780).

78787664 is an abundant number, since it is smaller than the sum of its proper divisors (79955896).

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

78787664 is a wasteful number, since it uses less digits than its factorization.

78787664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 927 (or 921 counting only the distinct ones).

The product of its digits is 3161088, while the sum is 53.

The square root of 78787664 is about 8876.2415469612. The cubic root of 78787664 is about 428.6992674292.

The spelling of 78787664 in words is "seventy-eight million, seven hundred eighty-seven thousand, six hundred sixty-four".