20664851 has 2 divisors, whose sum is σ = 20664852. Its totient is φ = 20664850.

The previous prime is 20664829. The next prime is 20664869. The reversal of 20664851 is 15846602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20664851 - 2²² = 16470547 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20664881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332425 + 10332426.

It is an arithmetic number, because the mean of its divisors is an integer number (10332426).

Almost surely, 2^20664851 is an apocalyptic number.

20664851 is a deficient number, since it is larger than the sum of its proper divisors (1).

20664851 is an equidigital number, since it uses as much as digits as its factorization.

20664851 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 20664851 is about 4545.8608645668. The cubic root of 20664851 is about 274.4168402698.

The spelling of 20664851 in words is "twenty million, six hundred sixty-four thousand, eight hundred fifty-one".