21770797 has 2 divisors, whose sum is σ = 21770798. Its totient is φ = 21770796.

The previous prime is 21770747. The next prime is 21770803. The reversal of 21770797 is 79707712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21706281 + 64516 = 4659^2 + 254^2 .

It is a cyclic number.

It is not a de Polignac number, because 21770797 - 2¹¹ = 21768749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21770747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10885398 + 10885399.

It is an arithmetic number, because the mean of its divisors is an integer number (10885399).

Almost surely, 2^21770797 is an apocalyptic number.

It is an amenable number.

21770797 is a deficient number, since it is larger than the sum of its proper divisors (1).

21770797 is an equidigital number, since it uses as much as digits as its factorization.

21770797 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43218, while the sum is 40.

The square root of 21770797 is about 4665.9186662436. The cubic root of 21770797 is about 279.2274494910.

The spelling of 21770797 in words is "twenty-one million, seven hundred seventy thousand, seven hundred ninety-seven".