21845401 has 2 divisors, whose sum is σ = 21845402. Its totient is φ = 21845400.

The previous prime is 21845387. The next prime is 21845431. The reversal of 21845401 is 10454812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14288400 + 7557001 = 3780^2 + 2749^2 .

It is a cyclic number.

It is not a de Polignac number, because 21845401 - 2²¹ = 19748249 is a prime.

It is not a weakly prime, because it can be changed into another prime (21845431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10922700 + 10922701.

It is an arithmetic number, because the mean of its divisors is an integer number (10922701).

Almost surely, 2^21845401 is an apocalyptic number.

It is an amenable number.

21845401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21845401 is an equidigital number, since it uses as much as digits as its factorization.

21845401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1280, while the sum is 25.

The square root of 21845401 is about 4673.9063961530. The cubic root of 21845401 is about 279.5460373495.

The spelling of 21845401 in words is "twenty-one million, eight hundred forty-five thousand, four hundred one".