81500438 has 16 divisors (see below), whose sum is σ = 123740160. Its totient is φ = 40257000.

The previous prime is 81500407. The next prime is 81500449. The reversal of 81500438 is 83400518.

It is a self number, because there is not a number n which added to its sum of digits gives 81500438.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63083 + ... + 64361.

It is an arithmetic number, because the mean of its divisors is an integer number (7733760).

Almost surely, 2^81500438 is an apocalyptic number.

81500438 is a deficient number, since it is larger than the sum of its proper divisors (42239722).

81500438 is a wasteful number, since it uses less digits than its factorization.

81500438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1643.

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 81500438 is about 9027.7593011777. The cubic root of 81500438 is about 433.5640997031.

The spelling of 81500438 in words is "eighty-one million, five hundred thousand, four hundred thirty-eight".