20751613 has 2 divisors, whose sum is σ = 20751614. Its totient is φ = 20751612.

The previous prime is 20751607. The next prime is 20751623. The reversal of 20751613 is 31615702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15077689 + 5673924 = 3883^2 + 2382^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20751613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20751623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10375806 + 10375807.

It is an arithmetic number, because the mean of its divisors is an integer number (10375807).

Almost surely, 2^20751613 is an apocalyptic number.

It is an amenable number.

20751613 is a deficient number, since it is larger than the sum of its proper divisors (1).

20751613 is an equidigital number, since it uses as much as digits as its factorization.

20751613 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 20751613 is about 4555.3938358829. The cubic root of 20751613 is about 274.8003531654.

The spelling of 20751613 in words is "twenty million, seven hundred fifty-one thousand, six hundred thirteen".