21858673 has 2 divisors, whose sum is σ = 21858674. Its totient is φ = 21858672.

The previous prime is 21858653. The next prime is 21858691. The reversal of 21858673 is 37685812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15944049 + 5914624 = 3993^2 + 2432^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21858673 is a prime.

It is not a weakly prime, because it can be changed into another prime (21858623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10929336 + 10929337.

It is an arithmetic number, because the mean of its divisors is an integer number (10929337).

Almost surely, 2^21858673 is an apocalyptic number.

It is an amenable number.

21858673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21858673 is an equidigital number, since it uses as much as digits as its factorization.

21858673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 80640, while the sum is 40.

The square root of 21858673 is about 4675.3259779399. The cubic root of 21858673 is about 279.6026378808.

The spelling of 21858673 in words is "twenty-one million, eight hundred fifty-eight thousand, six hundred seventy-three".