21446387 has 2 divisors, whose sum is σ = 21446388. Its totient is φ = 21446386.

The previous prime is 21446377. The next prime is 21446407. The reversal of 21446387 is 78364412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21446387 - 2⁴ = 21446371 is a prime.

It is not a weakly prime, because it can be changed into another prime (21446317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10723193 + 10723194.

It is an arithmetic number, because the mean of its divisors is an integer number (10723194).

Almost surely, 2^21446387 is an apocalyptic number.

21446387 is a deficient number, since it is larger than the sum of its proper divisors (1).

21446387 is an equidigital number, since it uses as much as digits as its factorization.

21446387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32256, while the sum is 35.

The square root of 21446387 is about 4631.0244007131. The cubic root of 21446387 is about 277.8335658201.

The spelling of 21446387 in words is "twenty-one million, four hundred forty-six thousand, three hundred eighty-seven".