21489401 has 2 divisors, whose sum is σ = 21489402. Its totient is φ = 21489400.

The previous prime is 21489389. The next prime is 21489407. The reversal of 21489401 is 10498412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11723776 + 9765625 = 3424^2 + 3125^2 .

It is a cyclic number.

It is not a de Polignac number, because 21489401 - 2¹⁴ = 21473017 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21489407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10744700 + 10744701.

It is an arithmetic number, because the mean of its divisors is an integer number (10744701).

Almost surely, 2^21489401 is an apocalyptic number.

It is an amenable number.

21489401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21489401 is an equidigital number, since it uses as much as digits as its factorization.

21489401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21489401 is about 4635.6661872917. Note that the first 3 decimals coincide. The cubic root of 21489401 is about 278.0191876410.

The spelling of 21489401 in words is "twenty-one million, four hundred eighty-nine thousand, four hundred one".