20720051 has 8 divisors (see below), whose sum is σ = 23793600. Its totient is φ = 17844840.

The previous prime is 20720039. The next prime is 20720057. The reversal of 20720051 is 15002702.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20720051 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20720057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49361 + ... + 49778.

It is an arithmetic number, because the mean of its divisors is an integer number (2974200).

Almost surely, 2^20720051 is an apocalyptic number.

20720051 is a deficient number, since it is larger than the sum of its proper divisors (3073549).

20720051 is a wasteful number, since it uses less digits than its factorization.

20720051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99169.

The product of its (nonzero) digits is 140, while the sum is 17.

The square root of 20720051 is about 4551.9282727214. The cubic root of 20720051 is about 274.6609640067.

Adding to 20720051 its reverse (15002702), we get a palindrome (35722753).

The spelling of 20720051 in words is "twenty million, seven hundred twenty thousand, fifty-one".