20919863 has 2 divisors, whose sum is σ = 20919864. Its totient is φ = 20919862.

The previous prime is 20919859. The next prime is 20919883. The reversal of 20919863 is 36891902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20919863 - 2² = 20919859 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 (20919883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10459931 + 10459932.

It is an arithmetic number, because the mean of its divisors is an integer number (10459932).

Almost surely, 2^20919863 is an apocalyptic number.

20919863 is a deficient number, since it is larger than the sum of its proper divisors (1).

20919863 is an equidigital number, since it uses as much as digits as its factorization.

20919863 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 20919863 is about 4573.8236739079. The cubic root of 20919863 is about 275.5410307542.

The spelling of 20919863 in words is "twenty million, nine hundred nineteen thousand, eight hundred sixty-three".