20661299 has 2 divisors, whose sum is σ = 20661300. Its totient is φ = 20661298.

The previous prime is 20661287. The next prime is 20661301. The reversal of 20661299 is 99216602.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20661299 is a prime.

Together with 20661301, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20667299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10330649 + 10330650.

It is an arithmetic number, because the mean of its divisors is an integer number (10330650).

Almost surely, 2^20661299 is an apocalyptic number.

20661299 is a deficient number, since it is larger than the sum of its proper divisors (1).

20661299 is an equidigital number, since it uses as much as digits as its factorization.

20661299 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 20661299 is about 4545.4701627004. The cubic root of 20661299 is about 274.4011165583.

The spelling of 20661299 in words is "twenty million, six hundred sixty-one thousand, two hundred ninety-nine".