21430723 has 2 divisors, whose sum is σ = 21430724. Its totient is φ = 21430722.

The previous prime is 21430697. The next prime is 21430753. The reversal of 21430723 is 32703412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21430723 - 2⁵ = 21430691 is a 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 = 21430694 and 21430703.

It is not a weakly prime, because it can be changed into another prime (21430753) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715361 + 10715362.

It is an arithmetic number, because the mean of its divisors is an integer number (10715362).

Almost surely, 2^21430723 is an apocalyptic number.

21430723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21430723 is an equidigital number, since it uses as much as digits as its factorization.

21430723 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 21430723 is about 4629.3328893049. The cubic root of 21430723 is about 277.7659080380.

The spelling of 21430723 in words is "twenty-one million, four hundred thirty thousand, seven hundred twenty-three".