21401593 has 2 divisors, whose sum is σ = 21401594. Its totient is φ = 21401592.

The previous prime is 21401557. The next prime is 21401617. The reversal of 21401593 is 39510412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15116544 + 6285049 = 3888^2 + 2507^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21401593 is a prime.

It is equal to p_1353751 and since 21401593 and 1353751 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21401693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700796 + 10700797.

It is an arithmetic number, because the mean of its divisors is an integer number (10700797).

Almost surely, 2^21401593 is an apocalyptic number.

It is an amenable number.

21401593 is a deficient number, since it is larger than the sum of its proper divisors (1).

21401593 is an equidigital number, since it uses as much as digits as its factorization.

21401593 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21401593 is about 4626.1855777736. The cubic root of 21401593 is about 277.6399986173.

The spelling of 21401593 in words is "twenty-one million, four hundred one thousand, five hundred ninety-three".