25221021 has 8 divisors (see below), whose sum is σ = 38432064. Its totient is φ = 14412000.

The previous prime is 25220963. The next prime is 25221023. The reversal of 25221021 is 12012252.

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

It is not a de Polignac number, because 25221021 - 2¹⁵ = 25188253 is a prime.

It is a Smith number, since the sum of its digits (15) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25221023) 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 7 ways as a sum of consecutive naturals, for example, 600480 + ... + 600521.

It is an arithmetic number, because the mean of its divisors is an integer number (4804008).

Almost surely, 2^25221021 is an apocalyptic number.

25221021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25221021 is a deficient number, since it is larger than the sum of its proper divisors (13211043).

25221021 is a wasteful number, since it uses less digits than its factorization.

25221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1201011.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 25221021 is about 5022.0534644705. The cubic root of 25221021 is about 293.2609392916.

Adding to 25221021 its reverse (12012252), we get a palindrome (37233273).

The spelling of 25221021 in words is "twenty-five million, two hundred twenty-one thousand, twenty-one".