21887447 has 2 divisors, whose sum is σ = 21887448. Its totient is φ = 21887446.

The previous prime is 21887429. The next prime is 21887479. The reversal of 21887447 is 74478812.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21887447 - 2¹⁶ = 21821911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21887417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10943723 + 10943724.

It is an arithmetic number, because the mean of its divisors is an integer number (10943724).

Almost surely, 2^21887447 is an apocalyptic number.

21887447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21887447 is an equidigital number, since it uses as much as digits as its factorization.

21887447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 100352, while the sum is 41.

The square root of 21887447 is about 4678.4021845070. The cubic root of 21887447 is about 279.7252704959.

The spelling of 21887447 in words is "twenty-one million, eight hundred eighty-seven thousand, four hundred forty-seven".