21173351 has 2 divisors, whose sum is σ = 21173352. Its totient is φ = 21173350.

The previous prime is 21173333. The next prime is 21173357. The reversal of 21173351 is 15337112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21173351 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21173357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10586675 + 10586676.

It is an arithmetic number, because the mean of its divisors is an integer number (10586676).

Almost surely, 2^21173351 is an apocalyptic number.

21173351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21173351 is an equidigital number, since it uses as much as digits as its factorization.

21173351 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 630, while the sum is 23.

The square root of 21173351 is about 4601.4509668147. The cubic root of 21173351 is about 276.6494847477.

The spelling of 21173351 in words is "twenty-one million, one hundred seventy-three thousand, three hundred fifty-one".