20725555 has 4 divisors (see below), whose sum is σ = 24870672. Its totient is φ = 16580440.

The previous prime is 20725547. The next prime is 20725589. The reversal of 20725555 is 55552702.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20725555 - 2³ = 20725547 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2072551 + ... + 2072560.

It is an arithmetic number, because the mean of its divisors is an integer number (6217668).

Almost surely, 2^20725555 is an apocalyptic number.

20725555 is a deficient number, since it is larger than the sum of its proper divisors (4145117).

20725555 is an equidigital number, since it uses as much as digits as its factorization.

20725555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4145116.

The product of its (nonzero) digits is 17500, while the sum is 31.

The square root of 20725555 is about 4552.5328115237. The cubic root of 20725555 is about 274.6852818379.

The spelling of 20725555 in words is "twenty million, seven hundred twenty-five thousand, five hundred fifty-five".