20725399 has 4 divisors (see below), whose sum is σ = 20734560. Its totient is φ = 20716240.

The previous prime is 20725387. The next prime is 20725403. The reversal of 20725399 is 99352702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20725399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20725339) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1539 + ... + 6619.

It is an arithmetic number, because the mean of its divisors is an integer number (5183640).

Almost surely, 2^20725399 is an apocalyptic number.

20725399 is a deficient number, since it is larger than the sum of its proper divisors (9161).

20725399 is an equidigital number, since it uses as much as digits as its factorization.

20725399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9160.

The product of its (nonzero) digits is 34020, while the sum is 37.

The square root of 20725399 is about 4552.5156781718. The cubic root of 20725399 is about 274.6845926563.

The spelling of 20725399 in words is "twenty million, seven hundred twenty-five thousand, three hundred ninety-nine".