21677723 has 2 divisors, whose sum is σ = 21677724. Its totient is φ = 21677722.

The previous prime is 21677717. The next prime is 21677741. The reversal of 21677723 is 32777612.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21677723 is a prime.

It is not a weakly prime, because it can be changed into another prime (21677713) 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, 10838861 + 10838862.

It is an arithmetic number, because the mean of its divisors is an integer number (10838862).

Almost surely, 2^21677723 is an apocalyptic number.

21677723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21677723 is an equidigital number, since it uses as much as digits as its factorization.

21677723 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24696, while the sum is 35.

The square root of 21677723 is about 4655.9341704968. The cubic root of 21677723 is about 278.8289655427.

The spelling of 21677723 in words is "twenty-one million, six hundred seventy-seven thousand, seven hundred twenty-three".