20631601 has 2 divisors, whose sum is σ = 20631602. Its totient is φ = 20631600.

The previous prime is 20631599. The next prime is 20631617. The reversal of 20631601 is 10613602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16120225 + 4511376 = 4015^2 + 2124^2 .

It is a cyclic number.

It is not a de Polignac number, because 20631601 - 2¹ = 20631599 is a prime.

Together with 20631599, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20631641) 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 as a sum of consecutive naturals, namely, 10315800 + 10315801.

It is an arithmetic number, because the mean of its divisors is an integer number (10315801).

Almost surely, 2^20631601 is an apocalyptic number.

It is an amenable number.

20631601 is a deficient number, since it is larger than the sum of its proper divisors (1).

20631601 is an equidigital number, since it uses as much as digits as its factorization.

20631601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 20631601 is about 4542.2022191884. The cubic root of 20631601 is about 274.2695812348.

The spelling of 20631601 in words is "twenty million, six hundred thirty-one thousand, six hundred one".