725138 has 4 divisors (see below), whose sum is σ = 1087710. Its totient is φ = 362568.

The previous prime is 725119. The next prime is 725147. The reversal of 725138 is 831527.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 831527 = 89 ⋅9343.

It can be written as a sum of positive squares in only one way, i.e., 683929 + 41209 = 827^2 + 203^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 181283 + ... + 181286.

2⁷²⁵¹³⁸ is an apocalyptic number.

725138 is a deficient number, since it is larger than the sum of its proper divisors (362572).

725138 is a wasteful number, since it uses less digits than its factorization.

725138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362571.

The product of its digits is 1680, while the sum is 26.

The square root of 725138 is about 851.5503508308. The cubic root of 725138 is about 89.8407884770.

The spelling of 725138 in words is "seven hundred twenty-five thousand, one hundred thirty-eight".