21628001 has 2 divisors, whose sum is σ = 21628002. Its totient is φ = 21628000.

The previous prime is 21627967. The next prime is 21628021. The reversal of 21628001 is 10082612.

It is an a-pointer prime, because the next prime (21628021) can be obtained adding 21628001 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13653025 + 7974976 = 3695^2 + 2824^2 .

It is a cyclic number.

It is not a de Polignac number, because 21628001 - 2⁶ = 21627937 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21628021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10814000 + 10814001.

It is an arithmetic number, because the mean of its divisors is an integer number (10814001).

Almost surely, 2^21628001 is an apocalyptic number.

It is an amenable number.

21628001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21628001 is an equidigital number, since it uses as much as digits as its factorization.

21628001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 21628001 is about 4650.5914677598. The cubic root of 21628001 is about 278.6156198388.

The spelling of 21628001 in words is "twenty-one million, six hundred twenty-eight thousand, one".