1993504081 has 4 divisors (see below), whose sum is σ = 1993979700. Its totient is φ = 1993028464.

The previous prime is 1993504061. The next prime is 1993504087. The reversal of 1993504081 is 1804053991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1804053991 = 17 ⋅106120823.

It can be written as a sum of positive squares in 2 ways, for example, as 1958505025 + 34999056 = 44255^2 + 5916^2 .

It is a cyclic number.

It is not a de Polignac number, because 1993504081 - 2⁵ = 1993504049 is a prime.

It is a super-2 number, since 2×1993504081² = 7948117041927309122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1993504087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231466 + ... + 239923.

It is an arithmetic number, because the mean of its divisors is an integer number (498494925).

Almost surely, 2^1993504081 is an apocalyptic number.

It is an amenable number.

1993504081 is a deficient number, since it is larger than the sum of its proper divisors (475619).

1993504081 is an equidigital number, since it uses as much as digits as its factorization.

1993504081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475618.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 1993504081 is about 44648.6738996804. The cubic root of 1993504081 is about 1258.5555129087. Note that the first 4 decimals are identical.

The spelling of 1993504081 in words is "one billion, nine hundred ninety-three million, five hundred four thousand, eighty-one".