21765299 has 2 divisors, whose sum is σ = 21765300. Its totient is φ = 21765298.

The previous prime is 21765259. The next prime is 21765307. The reversal of 21765299 is 99256712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21765299 - 2¹⁶ = 21699763 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21765209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10882649 + 10882650.

It is an arithmetic number, because the mean of its divisors is an integer number (10882650).

Almost surely, 2^21765299 is an apocalyptic number.

21765299 is a deficient number, since it is larger than the sum of its proper divisors (1).

21765299 is an equidigital number, since it uses as much as digits as its factorization.

21765299 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 41.

The square root of 21765299 is about 4665.3294631784. The cubic root of 21765299 is about 279.2039421328.

The spelling of 21765299 in words is "twenty-one million, seven hundred sixty-five thousand, two hundred ninety-nine".