81437785 has 16 divisors (see below), whose sum is σ = 114811200. Its totient is φ = 54671040.

The previous prime is 81437753. The next prime is 81437791. The reversal of 81437785 is 58773418.

It is not a de Polignac number, because 81437785 - 2⁵ = 81437753 is a prime.

It is a super-2 number, since 2×81437785² = 13264225651412450, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56235 + ... + 57664.

It is an arithmetic number, because the mean of its divisors is an integer number (7175700).

Almost surely, 2^81437785 is an apocalyptic number.

It is an amenable number.

81437785 is a deficient number, since it is larger than the sum of its proper divisors (33373415).

81437785 is a wasteful number, since it uses less digits than its factorization.

81437785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113928.

The product of its digits is 188160, while the sum is 43.

The square root of 81437785 is about 9024.2886146222. The cubic root of 81437785 is about 433.4529712399.

The spelling of 81437785 in words is "eighty-one million, four hundred thirty-seven thousand, seven hundred eighty-five".