20725509 has 8 divisors (see below), whose sum is σ = 31581760. Its totient is φ = 11843136.

The previous prime is 20725501. The next prime is 20725547. The reversal of 20725509 is 90552702.

It is a happy number.

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

It is not a de Polignac number, because 20725509 - 2³ = 20725501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20725501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 493444 + ... + 493485.

It is an arithmetic number, because the mean of its divisors is an integer number (3947720).

Almost surely, 2^20725509 is an apocalyptic number.

It is an amenable number.

20725509 is a deficient number, since it is larger than the sum of its proper divisors (10856251).

20725509 is an equidigital number, since it uses as much as digits as its factorization.

20725509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 986939.

The product of its (nonzero) digits is 6300, while the sum is 30.

The square root of 20725509 is about 4552.5277593882. The cubic root of 20725509 is about 274.6850786180.

The spelling of 20725509 in words is "twenty million, seven hundred twenty-five thousand, five hundred nine".