725984090209 has 9 divisors (see below), whose sum is σ = 844519043091. Its totient is φ = 622266965040.

The previous prime is 725984090101. The next prime is 725984090233. The reversal of 725984090209 is 902090489527.

The square root of 725984090209 is 852047.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 338203891809 + 387780198400 = 581553^2 + 622720^2 .

It is not a de Polignac number, because 725984090209 - 2⁷ = 725984090081 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 725984090209.

It is not an unprimeable number, because it can be changed into a prime (725984030209) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5903469 + ... + 6025189.

Almost surely, 2^725984090209 is an apocalyptic number.

725984090209 is the 852047-th square number.

725984090209 is the 426024-th centered octagonal number.

It is an amenable number.

725984090209 is a deficient number, since it is larger than the sum of its proper divisors (118534952882).

725984090209 is an frugal number, since it uses more digits than its factorization.

725984090209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243456 (or 121728 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 55.

The spelling of 725984090209 in words is "seven hundred twenty-five billion, nine hundred eighty-four million, ninety thousand, two hundred nine".