21494287 has 2 divisors, whose sum is σ = 21494288. Its totient is φ = 21494286.

The previous prime is 21494279. The next prime is 21494303. The reversal of 21494287 is 78249412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21494287 - 2³ = 21494279 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21494257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10747143 + 10747144.

It is an arithmetic number, because the mean of its divisors is an integer number (10747144).

Almost surely, 2^21494287 is an apocalyptic number.

21494287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21494287 is an equidigital number, since it uses as much as digits as its factorization.

21494287 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 37.

The square root of 21494287 is about 4636.1931581848. The cubic root of 21494287 is about 278.0402569240.

The spelling of 21494287 in words is "twenty-one million, four hundred ninety-four thousand, two hundred eighty-seven".