20989601 has 2 divisors, whose sum is σ = 20989602. Its totient is φ = 20989600.

The previous prime is 20989567. The next prime is 20989603. The reversal of 20989601 is 10698902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19351201 + 1638400 = 4399^2 + 1280^2 .

It is a cyclic number.

It is not a de Polignac number, because 20989601 - 2¹⁸ = 20727457 is a prime.

Together with 20989603, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20989603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10494800 + 10494801.

It is an arithmetic number, because the mean of its divisors is an integer number (10494801).

Almost surely, 2^20989601 is an apocalyptic number.

It is an amenable number.

20989601 is a deficient number, since it is larger than the sum of its proper divisors (1).

20989601 is an equidigital number, since it uses as much as digits as its factorization.

20989601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 20989601 is about 4581.4409305370. The cubic root of 20989601 is about 275.8468703532.

The spelling of 20989601 in words is "twenty million, nine hundred eighty-nine thousand, six hundred one".