21903653 has 2 divisors, whose sum is σ = 21903654. Its totient is φ = 21903652.

The previous prime is 21903647. The next prime is 21903677. The reversal of 21903653 is 35630912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12945604 + 8958049 = 3598^2 + 2993^2 .

It is a cyclic number.

It is not a de Polignac number, because 21903653 - 2⁸ = 21903397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21903643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10951826 + 10951827.

It is an arithmetic number, because the mean of its divisors is an integer number (10951827).

Almost surely, 2^21903653 is an apocalyptic number.

It is an amenable number.

21903653 is a deficient number, since it is larger than the sum of its proper divisors (1).

21903653 is an equidigital number, since it uses as much as digits as its factorization.

21903653 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4860, while the sum is 29.

The square root of 21903653 is about 4680.1338656068. The cubic root of 21903653 is about 279.7942919363.

The spelling of 21903653 in words is "twenty-one million, nine hundred three thousand, six hundred fifty-three".