21025023 has 4 divisors (see below), whose sum is σ = 28033368. Its totient is φ = 14016680.

The previous prime is 21025021. The next prime is 21025031. The reversal of 21025023 is 32052012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21025023 - 2¹ = 21025021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21024993 and 21025011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21025021) 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 3 ways as a sum of consecutive naturals, for example, 3504168 + ... + 3504173.

It is an arithmetic number, because the mean of its divisors is an integer number (7008342).

Almost surely, 2^21025023 is an apocalyptic number.

21025023 is a deficient number, since it is larger than the sum of its proper divisors (7008345).

21025023 is an equidigital number, since it uses as much as digits as its factorization.

21025023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7008344.

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 21025023 is about 4585.3051152568. The cubic root of 21025023 is about 276.0019559828.

Adding to 21025023 its reverse (32052012), we get a palindrome (53077035).

The spelling of 21025023 in words is "twenty-one million, twenty-five thousand, twenty-three".