20400019 has 2 divisors, whose sum is σ = 20400020. Its totient is φ = 20400018.

The previous prime is 20400013. The next prime is 20400031. The reversal of 20400019 is 91000402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20400019 - 2²³ = 12011411 is a prime.

It is a super-2 number, since 2×20400019² = 832321550400722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20399975 and 20400011.

It is not a weakly prime, because it can be changed into another prime (20400013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10200009 + 10200010.

It is an arithmetic number, because the mean of its divisors is an integer number (10200010).

Almost surely, 2^20400019 is an apocalyptic number.

20400019 is a deficient number, since it is larger than the sum of its proper divisors (1).

20400019 is an equidigital number, since it uses as much as digits as its factorization.

20400019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 20400019 is about 4516.6380195893. The cubic root of 20400019 is about 273.2395264387.

The spelling of 20400019 in words is "twenty million, four hundred thousand, nineteen".