20821623 has 8 divisors (see below), whose sum is σ = 28719600. Its totient is φ = 13402368.

The previous prime is 20821609. The next prime is 20821627. The reversal of 20821623 is 32612802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20821623 - 2⁴ = 20821607 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20821593 and 20821602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20821627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119578 + ... + 119751.

It is an arithmetic number, because the mean of its divisors is an integer number (3589950).

Almost surely, 2^20821623 is an apocalyptic number.

20821623 is a deficient number, since it is larger than the sum of its proper divisors (7897977).

20821623 is a wasteful number, since it uses less digits than its factorization.

20821623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239361.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 20821623 is about 4563.0716628166. The cubic root of 20821623 is about 275.1090388535.

The spelling of 20821623 in words is "twenty million, eight hundred twenty-one thousand, six hundred twenty-three".