21351593 has 2 divisors, whose sum is σ = 21351594. Its totient is φ = 21351592.

The previous prime is 21351571. The next prime is 21351601. The reversal of 21351593 is 39515312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21279769 + 71824 = 4613^2 + 268^2 .

It is a cyclic number.

It is not a de Polignac number, because 21351593 - 2²² = 17157289 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21351503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675796 + 10675797.

It is an arithmetic number, because the mean of its divisors is an integer number (10675797).

Almost surely, 2^21351593 is an apocalyptic number.

It is an amenable number.

21351593 is a deficient number, since it is larger than the sum of its proper divisors (1).

21351593 is an equidigital number, since it uses as much as digits as its factorization.

21351593 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4050, while the sum is 29.

The square root of 21351593 is about 4620.7783976296. The cubic root of 21351593 is about 277.4236155860.

The spelling of 21351593 in words is "twenty-one million, three hundred fifty-one thousand, five hundred ninety-three".