21425401 has 2 divisors, whose sum is σ = 21425402. Its totient is φ = 21425400.

The previous prime is 21425399. The next prime is 21425413. The reversal of 21425401 is 10452412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20259001 + 1166400 = 4501^2 + 1080^2 .

It is a cyclic number.

It is not a de Polignac number, because 21425401 - 2¹ = 21425399 is a prime.

Together with 21425399, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21425431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712700 + 10712701.

It is an arithmetic number, because the mean of its divisors is an integer number (10712701).

Almost surely, 2^21425401 is an apocalyptic number.

It is an amenable number.

21425401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21425401 is an equidigital number, since it uses as much as digits as its factorization.

21425401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21425401 is about 4628.7580407708. The cubic root of 21425401 is about 277.7429131294.

Adding to 21425401 its reverse (10452412), we get a palindrome (31877813).

The spelling of 21425401 in words is "twenty-one million, four hundred twenty-five thousand, four hundred one".