21025723 has 6 divisors (see below), whose sum is σ = 22190964. Its totient is φ = 19918764.

The previous prime is 21025691. The next prime is 21025729. The reversal of 21025723 is 32752012.

It is not a de Polignac number, because 21025723 - 2⁵ = 21025691 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21025694 and 21025703.

It is not an unprimeable number, because it can be changed into a prime (21025729) 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 in 5 ways as a sum of consecutive naturals, for example, 28761 + ... + 29482.

It is an arithmetic number, because the mean of its divisors is an integer number (3698494).

Almost surely, 2^21025723 is an apocalyptic number.

21025723 is a deficient number, since it is larger than the sum of its proper divisors (1165241).

21025723 is an equidigital number, since it uses as much as digits as its factorization.

21025723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58281 (or 58262 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21025723 is about 4585.3814454198. The cubic root of 21025723 is about 276.0050189874.

Adding to 21025723 its reverse (32752012), we get a palindrome (53777735).

The spelling of 21025723 in words is "twenty-one million, twenty-five thousand, seven hundred twenty-three".