20437819 has 2 divisors, whose sum is σ = 20437820. Its totient is φ = 20437818.

The previous prime is 20437817. The next prime is 20437829. The reversal of 20437819 is 91873402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20437819 - 2¹ = 20437817 is a prime.

It is a super-2 number, since 2×20437819² = 835408890953522, which contains 22 as substring.

Together with 20437817, it forms a pair of twin primes.

It is equal to p_1296565 and since 20437819 and 1296565 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (20437811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10218909 + 10218910.

It is an arithmetic number, because the mean of its divisors is an integer number (10218910).

Almost surely, 2^20437819 is an apocalyptic number.

20437819 is a deficient number, since it is larger than the sum of its proper divisors (1).

20437819 is an equidigital number, since it uses as much as digits as its factorization.

20437819 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 20437819 is about 4520.8206113492. The cubic root of 20437819 is about 273.4081877411.

The spelling of 20437819 in words is "twenty million, four hundred thirty-seven thousand, eight hundred nineteen".