25402021 has 2 divisors, whose sum is σ = 25402022. Its totient is φ = 25402020.

The previous prime is 25402019. The next prime is 25402033. The reversal of 25402021 is 12020452.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19096900 + 6305121 = 4370^2 + 2511^2 .

It is a cyclic number.

It is not a de Polignac number, because 25402021 - 2¹ = 25402019 is a prime.

Together with 25402019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 25401986 and 25402004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25402721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12701010 + 12701011.

It is an arithmetic number, because the mean of its divisors is an integer number (12701011).

Almost surely, 2^25402021 is an apocalyptic number.

It is an amenable number.

25402021 is a deficient number, since it is larger than the sum of its proper divisors (1).

25402021 is an equidigital number, since it uses as much as digits as its factorization.

25402021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 25402021 is about 5040.0417657000. The cubic root of 25402021 is about 293.9608019995.

Adding to 25402021 its reverse (12020452), we get a palindrome (37422473).

The spelling of 25402021 in words is "twenty-five million, four hundred two thousand, twenty-one".