25158821 has 2 divisors, whose sum is σ = 25158822. Its totient is φ = 25158820.

The previous prime is 25158811. The next prime is 25158823. The reversal of 25158821 is 12885152.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20702500 + 4456321 = 4550^2 + 2111^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25158821 is a prime.

It is a super-2 number, since 2×25158821² = 1265932548220082, which contains 22 as substring.

Together with 25158823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25158823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12579410 + 12579411.

It is an arithmetic number, because the mean of its divisors is an integer number (12579411).

Almost surely, 2^25158821 is an apocalyptic number.

It is an amenable number.

25158821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25158821 is an equidigital number, since it uses as much as digits as its factorization.

25158821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6400, while the sum is 32.

The square root of 25158821 is about 5015.8569556956. The cubic root of 25158821 is about 293.0196611112.

The spelling of 25158821 in words is "twenty-five million, one hundred fifty-eight thousand, eight hundred twenty-one".