20805529 has 2 divisors, whose sum is σ = 20805530. Its totient is φ = 20805528.

The previous prime is 20805517. The next prime is 20805539. The reversal of 20805529 is 92550802.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14440000 + 6365529 = 3800^2 + 2523^2 .

It is a cyclic number.

It is not a de Polignac number, because 20805529 - 2⁵ = 20805497 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 20805529.

It is not a weakly prime, because it can be changed into another prime (20805509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10402764 + 10402765.

It is an arithmetic number, because the mean of its divisors is an integer number (10402765).

Almost surely, 2^20805529 is an apocalyptic number.

It is an amenable number.

20805529 is a deficient number, since it is larger than the sum of its proper divisors (1).

20805529 is an equidigital number, since it uses as much as digits as its factorization.

20805529 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 20805529 is about 4561.3078168438. The cubic root of 20805529 is about 275.0381390630.

The spelling of 20805529 in words is "twenty million, eight hundred five thousand, five hundred twenty-nine".