20641571 has 2 divisors, whose sum is σ = 20641572. Its totient is φ = 20641570.

The previous prime is 20641559. The next prime is 20641589. The reversal of 20641571 is 17514602.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20641571 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20641571.

It is not a weakly prime, because it can be changed into another prime (20641541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10320785 + 10320786.

It is an arithmetic number, because the mean of its divisors is an integer number (10320786).

Almost surely, 2^20641571 is an apocalyptic number.

20641571 is a deficient number, since it is larger than the sum of its proper divisors (1).

20641571 is an equidigital number, since it uses as much as digits as its factorization.

20641571 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 20641571 is about 4543.2995718971. The cubic root of 20641571 is about 274.3137533986.

It can be divided in two parts, 20641 and 571, that added together give a palindrome (21212).

The spelling of 20641571 in words is "twenty million, six hundred forty-one thousand, five hundred seventy-one".