21426401 has 2 divisors, whose sum is σ = 21426402. Its totient is φ = 21426400.

The previous prime is 21426371. The next prime is 21426413. The reversal of 21426401 is 10462412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11566801 + 9859600 = 3401^2 + 3140^2 .

It is a cyclic number.

It is not a de Polignac number, because 21426401 - 2⁶ = 21426337 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21426421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713200 + 10713201.

It is an arithmetic number, because the mean of its divisors is an integer number (10713201).

Almost surely, 2^21426401 is an apocalyptic number.

It is an amenable number.

21426401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21426401 is an equidigital number, since it uses as much as digits as its factorization.

21426401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 21426401 is about 4628.8660598466. The cubic root of 21426401 is about 277.7472341468.

Adding to 21426401 its reverse (10462412), we get a palindrome (31888813).

The spelling of 21426401 in words is "twenty-one million, four hundred twenty-six thousand, four hundred one".