20725391 has 8 divisors (see below), whose sum is σ = 21456000. Its totient is φ = 19998720.

The previous prime is 20725387. The next prime is 20725403. The reversal of 20725391 is 19352702.

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

It is not a de Polignac number, because 20725391 - 2² = 20725387 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 (20725361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13175 + ... + 14663.

It is an arithmetic number, because the mean of its divisors is an integer number (2682000).

Almost surely, 2^20725391 is an apocalyptic number.

20725391 is a deficient number, since it is larger than the sum of its proper divisors (730609).

20725391 is a wasteful number, since it uses less digits than its factorization.

20725391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1969.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 20725391 is about 4552.5147995366. The cubic root of 20725391 is about 274.6845573136.

The spelling of 20725391 in words is "twenty million, seven hundred twenty-five thousand, three hundred ninety-one".