20631757 has 2 divisors, whose sum is σ = 20631758. Its totient is φ = 20631756.

The previous prime is 20631707. The next prime is 20631763. The reversal of 20631757 is 75713602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19236996 + 1394761 = 4386^2 + 1181^2 .

It is a cyclic number.

It is not a de Polignac number, because 20631757 - 2¹¹ = 20629709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20631707) 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 as a sum of consecutive naturals, namely, 10315878 + 10315879.

It is an arithmetic number, because the mean of its divisors is an integer number (10315879).

Almost surely, 2^20631757 is an apocalyptic number.

It is an amenable number.

20631757 is a deficient number, since it is larger than the sum of its proper divisors (1).

20631757 is an equidigital number, since it uses as much as digits as its factorization.

20631757 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8820, while the sum is 31.

The square root of 20631757 is about 4542.2193914429. The cubic root of 20631757 is about 274.2702725036.

The spelling of 20631757 in words is "twenty million, six hundred thirty-one thousand, seven hundred fifty-seven".