20859389 has 2 divisors, whose sum is σ = 20859390. Its totient is φ = 20859388.

The previous prime is 20859383. The next prime is 20859403. The reversal of 20859389 is 98395802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20839225 + 20164 = 4565^2 + 142^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20859389 is a prime.

It is a super-2 number, since 2×20859389² = 870228218906642, which contains 22 as substring.

It is a Sophie Germain 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 (20859383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10429694 + 10429695.

It is an arithmetic number, because the mean of its divisors is an integer number (10429695).

Almost surely, 2^20859389 is an apocalyptic number.

It is an amenable number.

20859389 is a deficient number, since it is larger than the sum of its proper divisors (1).

20859389 is an equidigital number, since it uses as much as digits as its factorization.

20859389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 20859389 is about 4567.2080092766. The cubic root of 20859389 is about 275.2752681731.

The spelling of 20859389 in words is "twenty million, eight hundred fifty-nine thousand, three hundred eighty-nine".