20453721 has 8 divisors (see below), whose sum is σ = 27296160. Its totient is φ = 13623552.

The previous prime is 20453717. The next prime is 20453743. The reversal of 20453721 is 12735402.

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

It is not a de Polignac number, because 20453721 - 2² = 20453717 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20453691 and 20453700.

It is not an unprimeable number, because it can be changed into a prime (20453701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2041 + ... + 6713.

It is an arithmetic number, because the mean of its divisors is an integer number (3412020).

Almost surely, 2^20453721 is an apocalyptic number.

It is an amenable number.

20453721 is a deficient number, since it is larger than the sum of its proper divisors (6842439).

20453721 is a wasteful number, since it uses less digits than its factorization.

20453721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6135.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 20453721 is about 4522.5790208685. The cubic root of 20453721 is about 273.4790793543.

The spelling of 20453721 in words is "twenty million, four hundred fifty-three thousand, seven hundred twenty-one".