20513819 has 2 divisors, whose sum is σ = 20513820. Its totient is φ = 20513818.

The previous prime is 20513791. The next prime is 20513827. The reversal of 20513819 is 91831502.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20513819 is a prime.

It is a super-2 number, since 2×20513819² = 841633539929522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 20513791 and 20513800.

It is not a weakly prime, because it can be changed into another prime (20513839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10256909 + 10256910.

It is an arithmetic number, because the mean of its divisors is an integer number (10256910).

Almost surely, 2^20513819 is an apocalyptic number.

20513819 is a deficient number, since it is larger than the sum of its proper divisors (1).

20513819 is an equidigital number, since it uses as much as digits as its factorization.

20513819 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 20513819 is about 4529.2183652370. The cubic root of 20513819 is about 273.7466667651.

The spelling of 20513819 in words is "twenty million, five hundred thirteen thousand, eight hundred nineteen".