20868439 has 2 divisors, whose sum is σ = 20868440. Its totient is φ = 20868438.

The previous prime is 20868433. The next prime is 20868443. The reversal of 20868439 is 93486802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20868439 - 2¹³ = 20860247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20868433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10434219 + 10434220.

It is an arithmetic number, because the mean of its divisors is an integer number (10434220).

Almost surely, 2^20868439 is an apocalyptic number.

20868439 is a deficient number, since it is larger than the sum of its proper divisors (1).

20868439 is an equidigital number, since it uses as much as digits as its factorization.

20868439 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82944, while the sum is 40.

The square root of 20868439 is about 4568.1986603036. The cubic root of 20868439 is about 275.3150724867.

The spelling of 20868439 in words is "twenty million, eight hundred sixty-eight thousand, four hundred thirty-nine".