21632657 has 2 divisors, whose sum is σ = 21632658. Its totient is φ = 21632656.

The previous prime is 21632651. The next prime is 21632671. The reversal of 21632657 is 75623612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13315201 + 8317456 = 3649^2 + 2884^2 .

It is a cyclic number.

It is not a de Polignac number, because 21632657 - 2⁴ = 21632641 is a prime.

It is not a weakly prime, because it can be changed into another prime (21632651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10816328 + 10816329.

It is an arithmetic number, because the mean of its divisors is an integer number (10816329).

Almost surely, 2^21632657 is an apocalyptic number.

It is an amenable number.

21632657 is a deficient number, since it is larger than the sum of its proper divisors (1).

21632657 is an equidigital number, since it uses as much as digits as its factorization.

21632657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 32.

The square root of 21632657 is about 4651.0920223105. The cubic root of 21632657 is about 278.6356115346.

The spelling of 21632657 in words is "twenty-one million, six hundred thirty-two thousand, six hundred fifty-seven".