81616338 has 24 divisors (see below), whose sum is σ = 177012108. Its totient is φ = 27178272.

The previous prime is 81616333. The next prime is 81616361. The reversal of 81616338 is 83361618.

81616338 is a `hidden beast` number, since 8 + 1 + 616 + 3 + 38 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 69105969 + 12510369 = 8313^2 + 3537^2 .

It is a super-2 number, since 2×81616338² = 13322453257060488, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81616333) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25356 + ... + 28392.

Almost surely, 2^81616338 is an apocalyptic number.

81616338 is an abundant number, since it is smaller than the sum of its proper divisors (95395770).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81616338 is a wasteful number, since it uses less digits than its factorization.

81616338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4538 (or 4535 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 81616338 is about 9034.1761107475. The cubic root of 81616338 is about 433.7695230494.

The spelling of 81616338 in words is "eighty-one million, six hundred sixteen thousand, three hundred thirty-eight".