20055721 has 8 divisors (see below), whose sum is σ = 22957760. Its totient is φ = 17162928.

The previous prime is 20055709. The next prime is 20055731. The reversal of 20055721 is 12755002.

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 20055721 - 2⁷ = 20055593 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20055692 and 20055701.

It is not an unprimeable number, because it can be changed into a prime (20055731) 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, 3235 + ... + 7111.

It is an arithmetic number, because the mean of its divisors is an integer number (2869720).

Almost surely, 2^20055721 is an apocalyptic number.

It is an amenable number.

20055721 is a deficient number, since it is larger than the sum of its proper divisors (2902039).

20055721 is an equidigital number, since it uses as much as digits as its factorization.

20055721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4623.

The product of its (nonzero) digits is 700, while the sum is 22.

The square root of 20055721 is about 4478.3614190907. The cubic root of 20055721 is about 271.6936113555.

The spelling of 20055721 in words is "twenty million, fifty-five thousand, seven hundred twenty-one".