21535601 has 2 divisors, whose sum is σ = 21535602. Its totient is φ = 21535600.

The previous prime is 21535589. The next prime is 21535621. The reversal of 21535601 is 10653512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13690000 + 7845601 = 3700^2 + 2801^2 .

It is a cyclic number.

It is not a de Polignac number, because 21535601 - 2¹⁰ = 21534577 is a prime.

It is a super-2 number, since 2×21535601² = 927564220862402, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21535621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10767800 + 10767801.

It is an arithmetic number, because the mean of its divisors is an integer number (10767801).

Almost surely, 2^21535601 is an apocalyptic number.

It is an amenable number.

21535601 is a deficient number, since it is larger than the sum of its proper divisors (1).

21535601 is an equidigital number, since it uses as much as digits as its factorization.

21535601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 21535601 is about 4640.6466144278. The cubic root of 21535601 is about 278.2182825758.

The spelling of 21535601 in words is "twenty-one million, five hundred thirty-five thousand, six hundred one".