21494729 has 2 divisors, whose sum is σ = 21494730. Its totient is φ = 21494728.

The previous prime is 21494723. The next prime is 21494779. The reversal of 21494729 is 92749412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19123129 + 2371600 = 4373^2 + 1540^2 .

It is a cyclic number.

It is not a de Polignac number, because 21494729 - 2¹⁶ = 21429193 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21494692 and 21494701.

It is not a weakly prime, because it can be changed into another prime (21494723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10747364 + 10747365.

It is an arithmetic number, because the mean of its divisors is an integer number (10747365).

Almost surely, 2^21494729 is an apocalyptic number.

It is an amenable number.

21494729 is a deficient number, since it is larger than the sum of its proper divisors (1).

21494729 is an equidigital number, since it uses as much as digits as its factorization.

21494729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 38.

The square root of 21494729 is about 4636.2408263592. The cubic root of 21494729 is about 278.0421627475.

The spelling of 21494729 in words is "twenty-one million, four hundred ninety-four thousand, seven hundred twenty-nine".