21713473 has 2 divisors, whose sum is σ = 21713474. Its totient is φ = 21713472.

The previous prime is 21713443. The next prime is 21713479. The reversal of 21713473 is 37431712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19775809 + 1937664 = 4447^2 + 1392^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21713473 is a prime.

It is not a weakly prime, because it can be changed into another prime (21713479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10856736 + 10856737.

It is an arithmetic number, because the mean of its divisors is an integer number (10856737).

Almost surely, 2^21713473 is an apocalyptic number.

It is an amenable number.

21713473 is a deficient number, since it is larger than the sum of its proper divisors (1).

21713473 is an equidigital number, since it uses as much as digits as its factorization.

21713473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3528, while the sum is 28.

The square root of 21713473 is about 4659.7717755272. The cubic root of 21713473 is about 278.9821590747.

The spelling of 21713473 in words is "twenty-one million, seven hundred thirteen thousand, four hundred seventy-three".