21769393 has 2 divisors, whose sum is σ = 21769394. Its totient is φ = 21769392.

The previous prime is 21769361. The next prime is 21769411. The reversal of 21769393 is 39396712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21464689 + 304704 = 4633^2 + 552^2 .

It is a cyclic number.

It is not a de Polignac number, because 21769393 - 2⁵ = 21769361 is a prime.

It is not a weakly prime, because it can be changed into another prime (21769313) 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, 10884696 + 10884697.

It is an arithmetic number, because the mean of its divisors is an integer number (10884697).

Almost surely, 2^21769393 is an apocalyptic number.

It is an amenable number.

21769393 is a deficient number, since it is larger than the sum of its proper divisors (1).

21769393 is an equidigital number, since it uses as much as digits as its factorization.

21769393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61236, while the sum is 40.

The square root of 21769393 is about 4665.7682111309. The cubic root of 21769393 is about 279.2214468970.

The spelling of 21769393 in words is "twenty-one million, seven hundred sixty-nine thousand, three hundred ninety-three".