81408424 has 32 divisors (see below), whose sum is σ = 157143240. Its totient is φ = 39520000.

The previous prime is 81408421. The next prime is 81408433. The reversal of 81408424 is 42480418.

It can be written as a sum of positive squares in 4 ways, for example, as 77123524 + 4284900 = 8782^2 + 2070^2 .

It is not an unprimeable number, because it can be changed into a prime (81408421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41874 + ... + 43774.

Almost surely, 2^81408424 is an apocalyptic number.

It is an amenable number.

81408424 is a deficient number, since it is larger than the sum of its proper divisors (75734816).

81408424 is a wasteful number, since it uses less digits than its factorization.

81408424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2061 (or 2057 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 31.

The square root of 81408424 is about 9022.6616915409. The cubic root of 81408424 is about 433.4008736276.

The spelling of 81408424 in words is "eighty-one million, four hundred eight thousand, four hundred twenty-four".