978858638 has 4 divisors (see below), whose sum is σ = 1468287960. Its totient is φ = 489429318.

The previous prime is 978858631. The next prime is 978858649. The reversal of 978858638 is 836858879.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 836858879 = 199 ⋅4205321.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (978858631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 244714658 + ... + 244714661.

It is an arithmetic number, because the mean of its divisors is an integer number (367071990).

Almost surely, 2^978858638 is an apocalyptic number.

978858638 is a deficient number, since it is larger than the sum of its proper divisors (489429322).

978858638 is a wasteful number, since it uses less digits than its factorization.

978858638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489429321.

The product of its digits is 23224320, while the sum is 62.

The square root of 978858638 is about 31286.7166382157. The cubic root of 978858638 is about 992.9026257839.

The spelling of 978858638 in words is "nine hundred seventy-eight million, eight hundred fifty-eight thousand, six hundred thirty-eight".