20813887 has 2 divisors, whose sum is σ = 20813888. Its totient is φ = 20813886.

The previous prime is 20813879. The next prime is 20813921. The reversal of 20813887 is 78831802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20813887 - 2³ = 20813879 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20813587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10406943 + 10406944.

It is an arithmetic number, because the mean of its divisors is an integer number (10406944).

Almost surely, 2^20813887 is an apocalyptic number.

20813887 is a deficient number, since it is larger than the sum of its proper divisors (1).

20813887 is an equidigital number, since it uses as much as digits as its factorization.

20813887 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 20813887 is about 4562.2239094547. The cubic root of 20813887 is about 275.0749635855.

The spelling of 20813887 in words is "twenty million, eight hundred thirteen thousand, eight hundred eighty-seven".