20649481 has 2 divisors, whose sum is σ = 20649482. Its totient is φ = 20649480.

The previous prime is 20649451. The next prime is 20649493. The reversal of 20649481 is 18494602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19404025 + 1245456 = 4405^2 + 1116^2 .

It is a cyclic number.

It is not a de Polignac number, because 20649481 - 2⁷ = 20649353 is a prime.

It is a super-2 number, since 2×20649481² = 852802131138722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20649451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10324740 + 10324741.

It is an arithmetic number, because the mean of its divisors is an integer number (10324741).

Almost surely, 2^20649481 is an apocalyptic number.

It is an amenable number.

20649481 is a deficient number, since it is larger than the sum of its proper divisors (1).

20649481 is an equidigital number, since it uses as much as digits as its factorization.

20649481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 20649481 is about 4544.1700012213. The cubic root of 20649481 is about 274.3487885982.

The spelling of 20649481 in words is "twenty million, six hundred forty-nine thousand, four hundred eighty-one".