25220421 has 24 divisors (see below), whose sum is σ = 38146680. Its totient is φ = 16039296.

The previous prime is 25220417. The next prime is 25220423. The reversal of 25220421 is 12402252.

25220421 is a `hidden beast` number, since 25 + 220 + 421 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 5239521 + 19980900 = 2289^2 + 4470^2 .

It is not a de Polignac number, because 25220421 - 2² = 25220417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 25220394 and 25220403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25220423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16935 + ... + 18363.

It is an arithmetic number, because the mean of its divisors is an integer number (1589445).

Almost surely, 2^25220421 is an apocalyptic number.

It is an amenable number.

25220421 is a deficient number, since it is larger than the sum of its proper divisors (12926259).

25220421 is a wasteful number, since it uses less digits than its factorization.

25220421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525 (or 1522 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 25220421 is about 5021.9937275946. The cubic root of 25220421 is about 293.2586137452.

Adding to 25220421 its reverse (12402252), we get a palindrome (37622673).

The spelling of 25220421 in words is "twenty-five million, two hundred twenty thousand, four hundred twenty-one".