398726138 has 4 divisors (see below), whose sum is σ = 598089210. Its totient is φ = 199363068.

The previous prime is 398726117. The next prime is 398726161. The reversal of 398726138 is 831627893.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 831627893 = 227 ⋅3663559.

It can be written as a sum of positive squares in only one way, i.e., 385454689 + 13271449 = 19633^2 + 3643^2 .

It is a junction number, because it is equal to n+sod(n) for n = 398726092 and 398726101.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99681533 + ... + 99681536.

Almost surely, 2^398726138 is an apocalyptic number.

398726138 is a deficient number, since it is larger than the sum of its proper divisors (199363072).

398726138 is a wasteful number, since it uses less digits than its factorization.

398726138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199363071.

The product of its digits is 435456, while the sum is 47.

The square root of 398726138 is about 19968.1280544772. The cubic root of 398726138 is about 736.0233099994.

The spelling of 398726138 in words is "three hundred ninety-eight million, seven hundred twenty-six thousand, one hundred thirty-eight".