20847481 has 2 divisors, whose sum is σ = 20847482. Its totient is φ = 20847480.

The previous prime is 20847451. The next prime is 20847493. The reversal of 20847481 is 18474802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12673600 + 8173881 = 3560^2 + 2859^2 .

It is a cyclic number.

It is not a de Polignac number, because 20847481 - 2⁷ = 20847353 is a prime.

It is a super-2 number, since 2×20847481² = 869234928090722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20847401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10423740 + 10423741.

It is an arithmetic number, because the mean of its divisors is an integer number (10423741).

Almost surely, 2^20847481 is an apocalyptic number.

It is an amenable number.

20847481 is a deficient number, since it is larger than the sum of its proper divisors (1).

20847481 is an equidigital number, since it uses as much as digits as its factorization.

20847481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14336, while the sum is 34.

The square root of 20847481 is about 4565.9041820870. The cubic root of 20847481 is about 275.2228760687. Note that the first 3 decimals are identical.

The spelling of 20847481 in words is "twenty million, eight hundred forty-seven thousand, four hundred eighty-one".