20720665 has 8 divisors (see below), whose sum is σ = 28416960. Its totient is φ = 14208432.

The previous prime is 20720653. The next prime is 20720681. The reversal of 20720665 is 56602702.

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

It is not a de Polignac number, because 20720665 - 2⁵ = 20720633 is a prime.

It is an unprimeable number.

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, 295975 + ... + 296044.

It is an arithmetic number, because the mean of its divisors is an integer number (3552120).

Almost surely, 2^20720665 is an apocalyptic number.

It is an amenable number.

20720665 is a deficient number, since it is larger than the sum of its proper divisors (7696295).

20720665 is an equidigital number, since it uses as much as digits as its factorization.

20720665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 592031.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 20720665 is about 4551.9957161667. The cubic root of 20720665 is about 274.6636770014.

The spelling of 20720665 in words is "twenty million, seven hundred twenty thousand, six hundred sixty-five".