20819213 has 2 divisors, whose sum is σ = 20819214. Its totient is φ = 20819212.

The previous prime is 20819173. The next prime is 20819243. The reversal of 20819213 is 31291802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19731364 + 1087849 = 4442^2 + 1043^2 .

It is a cyclic number.

It is not a de Polignac number, because 20819213 - 2¹² = 20815117 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 (20819243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10409606 + 10409607.

It is an arithmetic number, because the mean of its divisors is an integer number (10409607).

Almost surely, 2^20819213 is an apocalyptic number.

It is an amenable number.

20819213 is a deficient number, since it is larger than the sum of its proper divisors (1).

20819213 is an equidigital number, since it uses as much as digits as its factorization.

20819213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 20819213 is about 4562.8075786735. The cubic root of 20819213 is about 275.0984242732.

The spelling of 20819213 in words is "twenty million, eight hundred nineteen thousand, two hundred thirteen".