20523869 has 2 divisors, whose sum is σ = 20523870. Its totient is φ = 20523868.

The previous prime is 20523859. The next prime is 20523887. The reversal of 20523869 is 96832502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17530969 + 2992900 = 4187^2 + 1730^2 .

It is a cyclic number.

It is not a de Polignac number, because 20523869 - 2¹² = 20519773 is a prime.

It is a super-2 number, since 2×20523869² = 842458397458322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20523809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10261934 + 10261935.

It is an arithmetic number, because the mean of its divisors is an integer number (10261935).

Almost surely, 2^20523869 is an apocalyptic number.

It is an amenable number.

20523869 is a deficient number, since it is larger than the sum of its proper divisors (1).

20523869 is an equidigital number, since it uses as much as digits as its factorization.

20523869 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 20523869 is about 4530.3276923419. The cubic root of 20523869 is about 273.7913635432.

The spelling of 20523869 in words is "twenty million, five hundred twenty-three thousand, eight hundred sixty-nine".