9921601 has 2 divisors, whose sum is σ = 9921602. Its totient is φ = 9921600.

The previous prime is 9921599. The next prime is 9921619. The reversal of 9921601 is 1061299.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9859600 + 62001 = 3140^2 + 249^2 .

It is a cyclic number.

It is not a de Polignac number, because 9921601 - 2¹ = 9921599 is a prime.

Together with 9921599, it forms a pair of twin primes.

It is a Chen prime.

It is a nialpdrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 9921601.

It is not a weakly prime, because it can be changed into another prime (9921641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4960800 + 4960801.

It is an arithmetic number, because the mean of its divisors is an integer number (4960801).

Almost surely, 2^9921601 is an apocalyptic number.

It is an amenable number.

9921601 is a deficient number, since it is larger than the sum of its proper divisors (1).

9921601 is an equidigital number, since it uses as much as digits as its factorization.

9921601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 9921601 is about 3149.8572983550. The cubic root of 9921601 is about 214.8789728075.

The spelling of 9921601 in words is "nine million, nine hundred twenty-one thousand, six hundred one".