21677399 has 2 divisors, whose sum is σ = 21677400. Its totient is φ = 21677398.

The previous prime is 21677389. The next prime is 21677407. The reversal of 21677399 is 99377612.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21677399 - 2¹² = 21673303 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21677389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10838699 + 10838700.

It is an arithmetic number, because the mean of its divisors is an integer number (10838700).

Almost surely, 2^21677399 is an apocalyptic number.

21677399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21677399 is an equidigital number, since it uses as much as digits as its factorization.

21677399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 142884, while the sum is 44.

The square root of 21677399 is about 4655.8993760604. The cubic root of 21677399 is about 278.8275763895.

The spelling of 21677399 in words is "twenty-one million, six hundred seventy-seven thousand, three hundred ninety-nine".