1978398838 has 24 divisors (see below), whose sum is σ = 3217289328. Its totient is φ = 912012192.

The previous prime is 1978398757. The next prime is 1978398839. The reversal of 1978398838 is 8388938791.

It is a self number, because there is not a number n which added to its sum of digits gives 1978398838.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978398839) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 323820 + ... + 329872.

It is an arithmetic number, because the mean of its divisors is an integer number (134053722).

Almost surely, 2^1978398838 is an apocalyptic number.

1978398838 is a deficient number, since it is larger than the sum of its proper divisors (1238890490).

1978398838 is a wasteful number, since it uses less digits than its factorization.

1978398838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7048 (or 7035 counting only the distinct ones).

The product of its digits is 20901888, while the sum is 64.

The square root of 1978398838 is about 44479.1955637689. The cubic root of 1978398838 is about 1255.3686610784.

The spelling of 1978398838 in words is "one billion, nine hundred seventy-eight million, three hundred ninety-eight thousand, eight hundred thirty-eight".