19805481 has 6 divisors (see below), whose sum is σ = 28607930. Its totient is φ = 13203648.

The previous prime is 19805479. The next prime is 19805509. The reversal of 19805481 is 18450891.

It can be written as a sum of positive squares in only one way, i.e., 15139881 + 4665600 = 3891^2 + 2160^2 .

It is not a de Polignac number, because 19805481 - 2¹ = 19805479 is a prime.

It is a super-2 number, since 2×19805481² = 784514155282722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19805441) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1100296 + ... + 1100313.

Almost surely, 2^19805481 is an apocalyptic number.

It is an amenable number.

19805481 is a deficient number, since it is larger than the sum of its proper divisors (8802449).

19805481 is a wasteful number, since it uses less digits than its factorization.

19805481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200615 (or 2200612 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 19805481 is about 4450.3349312159. The cubic root of 19805481 is about 270.5588834994.

It can be divided in two parts, 198054 and 81, that added together give a triangular number (198135 = T₆₂₉).

The spelling of 19805481 in words is "nineteen million, eight hundred five thousand, four hundred eighty-one".