21447407 has 2 divisors, whose sum is σ = 21447408. Its totient is φ = 21447406.

The previous prime is 21447397. The next prime is 21447427. The reversal of 21447407 is 70474412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21447407 - 2¹² = 21443311 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21447407.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21447427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10723703 + 10723704.

It is an arithmetic number, because the mean of its divisors is an integer number (10723704).

Almost surely, 2^21447407 is an apocalyptic number.

21447407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21447407 is an equidigital number, since it uses as much as digits as its factorization.

21447407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6272, while the sum is 29.

The square root of 21447407 is about 4631.1345262257. The cubic root of 21447407 is about 277.8379703809.

The spelling of 21447407 in words is "twenty-one million, four hundred forty-seven thousand, four hundred seven".