725691 has 8 divisors (see below), whose sum is σ = 981504. Its totient is φ = 476840.

The previous prime is 725687. The next prime is 725723. The reversal of 725691 is 196527.

725691 = T₁₀₆ + T₁₀₇ + ... + T₁₇₆.

725691 = 64² + 65² + ... + 134².

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 725691 - 2² = 725687 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (725671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1491 + ... + 1916.

It is an arithmetic number, because the mean of its divisors is an integer number (122688).

2⁷²⁵⁶⁹¹ is an apocalyptic number.

725691 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

725691 is a deficient number, since it is larger than the sum of its proper divisors (255813).

725691 is a wasteful number, since it uses less digits than its factorization.

725691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3481.

The product of its digits is 3780, while the sum is 30.

The square root of 725691 is about 851.8749908291. The cubic root of 725691 is about 89.8636206056.

The spelling of 725691 in words is "seven hundred twenty-five thousand, six hundred ninety-one".