21545653 has 2 divisors, whose sum is σ = 21545654. Its totient is φ = 21545652.

The previous prime is 21545621. The next prime is 21545663. The reversal of 21545653 is 35654512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17123044 + 4422609 = 4138^2 + 2103^2 .

It is a cyclic number.

It is not a de Polignac number, because 21545653 - 2⁵ = 21545621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21545603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10772826 + 10772827.

It is an arithmetic number, because the mean of its divisors is an integer number (10772827).

Almost surely, 2^21545653 is an apocalyptic number.

It is an amenable number.

21545653 is a deficient number, since it is larger than the sum of its proper divisors (1).

21545653 is an equidigital number, since it uses as much as digits as its factorization.

21545653 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18000, while the sum is 31.

The square root of 21545653 is about 4641.7295268036. The cubic root of 21545653 is about 278.2615630824.

The spelling of 21545653 in words is "twenty-one million, five hundred forty-five thousand, six hundred fifty-three".