20649571 has 2 divisors, whose sum is σ = 20649572. Its totient is φ = 20649570.

The previous prime is 20649557. The next prime is 20649581. The reversal of 20649571 is 17594602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20649571 - 2⁵ = 20649539 is a prime.

It is not a weakly prime, because it can be changed into another prime (20649581) 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, 10324785 + 10324786.

It is an arithmetic number, because the mean of its divisors is an integer number (10324786).

Almost surely, 2^20649571 is an apocalyptic number.

20649571 is a deficient number, since it is larger than the sum of its proper divisors (1).

20649571 is an equidigital number, since it uses as much as digits as its factorization.

20649571 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 20649571 is about 4544.1799040091. The cubic root of 20649571 is about 274.3491871773.

The spelling of 20649571 in words is "twenty million, six hundred forty-nine thousand, five hundred seventy-one".