81990603 has 16 divisors (see below), whose sum is σ = 121998240. Its totient is φ = 54421632.

The previous prime is 81990599. The next prime is 81990613. The reversal of 81990603 is 30609918.

It is not a de Polignac number, because 81990603 - 2² = 81990599 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81990613) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 226 + ... + 12807.

It is an arithmetic number, because the mean of its divisors is an integer number (7624890).

Almost surely, 2^81990603 is an apocalyptic number.

81990603 is a deficient number, since it is larger than the sum of its proper divisors (40007637).

81990603 is a wasteful number, since it uses less digits than its factorization.

81990603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13275 (or 13269 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 81990603 is about 9054.8662607462. The cubic root of 81990603 is about 434.4315523768.

The spelling of 81990603 in words is "eighty-one million, nine hundred ninety thousand, six hundred three".