78638740 has 24 divisors (see below), whose sum is σ = 167942880. Its totient is φ = 30921888.

The previous prime is 78638737. The next prime is 78638743. The reversal of 78638740 is 4783687.

It is an interprime number because it is at equal distance from previous prime (78638737) and next prime (78638743).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78638743) 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, 32142 + ... + 34501.

It is an arithmetic number, because the mean of its divisors is an integer number (6997620).

Almost surely, 2^78638740 is an apocalyptic number.

It is an amenable number.

78638740 is an abundant number, since it is smaller than the sum of its proper divisors (89304140).

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

78638740 is a wasteful number, since it uses less digits than its factorization.

78638740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66711 (or 66709 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 43.

The square root of 78638740 is about 8867.8486680818. The cubic root of 78638740 is about 428.4289887487.

The spelling of 78638740 in words is "seventy-eight million, six hundred thirty-eight thousand, seven hundred forty".