21603733 has 2 divisors, whose sum is σ = 21603734. Its totient is φ = 21603732.

The previous prime is 21603661. The next prime is 21603749. The reversal of 21603733 is 33730612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11881809 + 9721924 = 3447^2 + 3118^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21603733 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21603698 and 21603707.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21603763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10801866 + 10801867.

It is an arithmetic number, because the mean of its divisors is an integer number (10801867).

Almost surely, 2^21603733 is an apocalyptic number.

It is an amenable number.

21603733 is a deficient number, since it is larger than the sum of its proper divisors (1).

21603733 is an equidigital number, since it uses as much as digits as its factorization.

21603733 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 25.

The square root of 21603733 is about 4647.9816049550. The cubic root of 21603733 is about 278.5113726585.

The spelling of 21603733 in words is "twenty-one million, six hundred three thousand, seven hundred thirty-three".