21432473 has 2 divisors, whose sum is σ = 21432474. Its totient is φ = 21432472.

The previous prime is 21432443. The next prime is 21432493. The reversal of 21432473 is 37423412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14531344 + 6901129 = 3812^2 + 2627^2 .

It is a cyclic number.

It is not a de Polignac number, because 21432473 - 2⁶ = 21432409 is a prime.

It is not a weakly prime, because it can be changed into another prime (21432403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716236 + 10716237.

It is an arithmetic number, because the mean of its divisors is an integer number (10716237).

Almost surely, 2^21432473 is an apocalyptic number.

It is an amenable number.

21432473 is a deficient number, since it is larger than the sum of its proper divisors (1).

21432473 is an equidigital number, since it uses as much as digits as its factorization.

21432473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 26.

The square root of 21432473 is about 4629.5218975613. The cubic root of 21432473 is about 277.7734684783.

Adding to 21432473 its reverse (37423412), we get a palindrome (58855885).

The spelling of 21432473 in words is "twenty-one million, four hundred thirty-two thousand, four hundred seventy-three".