21051673 has 2 divisors, whose sum is σ = 21051674. Its totient is φ = 21051672.

The previous prime is 21051643. The next prime is 21051691. The reversal of 21051673 is 37615012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14538969 + 6512704 = 3813^2 + 2552^2 .

It is a cyclic number.

It is not a de Polignac number, because 21051673 - 2¹³ = 21043481 is a prime.

It is not a weakly prime, because it can be changed into another prime (21051623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525836 + 10525837.

It is an arithmetic number, because the mean of its divisors is an integer number (10525837).

Almost surely, 2^21051673 is an apocalyptic number.

It is an amenable number.

21051673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21051673 is an equidigital number, since it uses as much as digits as its factorization.

21051673 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 21051673 is about 4588.2102175031. The cubic root of 21051673 is about 276.1185210006.

Adding to 21051673 its reverse (37615012), we get a palindrome (58666685).

The spelling of 21051673 in words is "twenty-one million, fifty-one thousand, six hundred seventy-three".