138872978 has 4 divisors (see below), whose sum is σ = 208309470. Its totient is φ = 69436488.

The previous prime is 138872959. The next prime is 138872999. The reversal of 138872978 is 879278831.

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., 104919049 + 33953929 = 10243^2 + 5827^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34718243 + ... + 34718246.

Almost surely, 2^138872978 is an apocalyptic number.

138872978 is a deficient number, since it is larger than the sum of its proper divisors (69436492).

138872978 is an equidigital number, since it uses as much as digits as its factorization.

138872978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69436491.

The product of its digits is 1354752, while the sum is 53.

The square root of 138872978 is about 11784.4379585961. The cubic root of 138872978 is about 517.8523080380.

The spelling of 138872978 in words is "one hundred thirty-eight million, eight hundred seventy-two thousand, nine hundred seventy-eight".