285518661981 has 36 divisors (see below), whose sum is σ = 467379722592. Its totient is φ = 154566464976.

The previous prime is 285518661977. The next prime is 285518662027. The reversal of 285518661981 is 189166815582.

It is not a de Polignac number, because 285518661981 - 2² = 285518661977 is a prime.

It is a super-2 number, since 2×285518661981² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (285518661881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2637105 + ... + 2743238.

It is an arithmetic number, because the mean of its divisors is an integer number (12982770072).

Almost surely, 2^285518661981 is an apocalyptic number.

285518661981 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

285518661981 is a deficient number, since it is larger than the sum of its proper divisors (181861060611).

285518661981 is a wasteful number, since it uses less digits than its factorization.

285518661981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5380398 (or 5380372 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 60.

The spelling of 285518661981 in words is "two hundred eighty-five billion, five hundred eighteen million, six hundred sixty-one thousand, nine hundred eighty-one".