20489621 has 2 divisors, whose sum is σ = 20489622. Its totient is φ = 20489620.

The previous prime is 20489617. The next prime is 20489647. The reversal of 20489621 is 12698402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10817521 + 9672100 = 3289^2 + 3110^2 .

It is a cyclic number.

It is not a de Polignac number, because 20489621 - 2² = 20489617 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_1299614 and since 20489621 and 1299614 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20489611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10244810 + 10244811.

It is an arithmetic number, because the mean of its divisors is an integer number (10244811).

Almost surely, 2^20489621 is an apocalyptic number.

It is an amenable number.

20489621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20489621 is an equidigital number, since it uses as much as digits as its factorization.

20489621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 20489621 is about 4526.5462551486. The cubic root of 20489621 is about 273.6389876741.

The spelling of 20489621 in words is "twenty million, four hundred eighty-nine thousand, six hundred twenty-one".