21159533 has 2 divisors, whose sum is σ = 21159534. Its totient is φ = 21159532.

The previous prime is 21159529. The next prime is 21159539. The reversal of 21159533 is 33595112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15389929 + 5769604 = 3923^2 + 2402^2 .

It is a cyclic number.

It is not a de Polignac number, because 21159533 - 2² = 21159529 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21159496 and 21159505.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21159539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10579766 + 10579767.

It is an arithmetic number, because the mean of its divisors is an integer number (10579767).

Almost surely, 2^21159533 is an apocalyptic number.

It is an amenable number.

21159533 is a deficient number, since it is larger than the sum of its proper divisors (1).

21159533 is an equidigital number, since it uses as much as digits as its factorization.

21159533 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 21159533 is about 4599.9492388504. The cubic root of 21159533 is about 276.5892899857.

The spelling of 21159533 in words is "twenty-one million, one hundred fifty-nine thousand, five hundred thirty-three".