78640258 has 4 divisors (see below), whose sum is σ = 117960390. Its totient is φ = 39320128.

The previous prime is 78640229. The next prime is 78640271. The reversal of 78640258 is 85204687.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 54952569 + 23687689 = 7413^2 + 4867^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 78640258.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19660063 + ... + 19660066.

Almost surely, 2^78640258 is an apocalyptic number.

78640258 is a deficient number, since it is larger than the sum of its proper divisors (39320132).

78640258 is a wasteful number, since it uses less digits than its factorization.

78640258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39320131.

The product of its (nonzero) digits is 107520, while the sum is 40.

The square root of 78640258 is about 8867.9342577626. The cubic root of 78640258 is about 428.4317454520.

The spelling of 78640258 in words is "seventy-eight million, six hundred forty thousand, two hundred fifty-eight".