21575723 has 12 divisors (see below), whose sum is σ = 23914440. Its totient is φ = 19446336.

The previous prime is 21575677. The next prime is 21575747. The reversal of 21575723 is 32757512.

It is not a de Polignac number, because 21575723 - 2⁸ = 21575467 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21575723.

It is not an unprimeable number, because it can be changed into a prime (21575753) 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 in 11 ways as a sum of consecutive naturals, for example, 5783 + ... + 8751.

It is an arithmetic number, because the mean of its divisors is an integer number (1992870).

Almost surely, 2^21575723 is an apocalyptic number.

21575723 is a deficient number, since it is larger than the sum of its proper divisors (2338717).

21575723 is a wasteful number, since it uses less digits than its factorization.

21575723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3038 (or 3025 counting only the distinct ones).

The product of its digits is 14700, while the sum is 32.

The square root of 21575723 is about 4644.9674918130. The cubic root of 21575723 is about 278.3909540029.

The spelling of 21575723 in words is "twenty-one million, five hundred seventy-five thousand, seven hundred twenty-three".