20806619 has 2 divisors, whose sum is σ = 20806620. Its totient is φ = 20806618.

The previous prime is 20806613. The next prime is 20806631. The reversal of 20806619 is 91660802.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20806619 is a prime.

It is a super-2 number, since 2×20806619² = 865830788422322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20806613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10403309 + 10403310.

It is an arithmetic number, because the mean of its divisors is an integer number (10403310).

Almost surely, 2^20806619 is an apocalyptic number.

20806619 is a deficient number, since it is larger than the sum of its proper divisors (1).

20806619 is an equidigital number, since it uses as much as digits as its factorization.

20806619 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 20806619 is about 4561.4272985547. The cubic root of 20806619 is about 275.0429420545.

The spelling of 20806619 in words is "twenty million, eight hundred six thousand, six hundred nineteen".