20647801 has 2 divisors, whose sum is σ = 20647802. Its totient is φ = 20647800.

The previous prime is 20647777. The next prime is 20647807. The reversal of 20647801 is 10874602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17842176 + 2805625 = 4224^2 + 1675^2 .

It is a cyclic number.

It is not a de Polignac number, because 20647801 - 2⁵ = 20647769 is a prime.

It is a super-2 number, since 2×20647801² = 852663372271202, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20647801.

It is not a weakly prime, because it can be changed into another prime (20647807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10323900 + 10323901.

It is an arithmetic number, because the mean of its divisors is an integer number (10323901).

Almost surely, 2^20647801 is an apocalyptic number.

It is an amenable number.

20647801 is a deficient number, since it is larger than the sum of its proper divisors (1).

20647801 is an equidigital number, since it uses as much as digits as its factorization.

20647801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 20647801 is about 4543.9851452222. The cubic root of 20647801 is about 274.3413482423.

The spelling of 20647801 in words is "twenty million, six hundred forty-seven thousand, eight hundred one".