21630601 has 2 divisors, whose sum is σ = 21630602. Its totient is φ = 21630600.

The previous prime is 21630593. The next prime is 21630611. The reversal of 21630601 is 10603612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13133376 + 8497225 = 3624^2 + 2915^2 .

It is a cyclic number.

It is not a de Polignac number, because 21630601 - 2³ = 21630593 is a prime.

It is not a weakly prime, because it can be changed into another prime (21630611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10815300 + 10815301.

It is an arithmetic number, because the mean of its divisors is an integer number (10815301).

Almost surely, 2^21630601 is an apocalyptic number.

It is an amenable number.

21630601 is a deficient number, since it is larger than the sum of its proper divisors (1).

21630601 is an equidigital number, since it uses as much as digits as its factorization.

21630601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 21630601 is about 4650.8709936957. The cubic root of 21630601 is about 278.6267839402.

The spelling of 21630601 in words is "twenty-one million, six hundred thirty thousand, six hundred one".