81854137 has 4 divisors (see below), whose sum is σ = 82664676. Its totient is φ = 81043600.

The previous prime is 81854107. The next prime is 81854197. The reversal of 81854137 is 73145818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 58660281 + 23193856 = 7659^2 + 4816^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81854137 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81854096 and 81854105.

It is not an unprimeable number, because it can be changed into a prime (81854107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 405118 + ... + 405319.

It is an arithmetic number, because the mean of its divisors is an integer number (20666169).

Almost surely, 2^81854137 is an apocalyptic number.

It is an amenable number.

81854137 is a deficient number, since it is larger than the sum of its proper divisors (810539).

81854137 is a wasteful number, since it uses less digits than its factorization.

81854137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 810538.

The product of its digits is 26880, while the sum is 37.

The square root of 81854137 is about 9047.3276164843. The cubic root of 81854137 is about 434.1903944225.

The spelling of 81854137 in words is "eighty-one million, eight hundred fifty-four thousand, one hundred thirty-seven".