81858655 has 8 divisors (see below), whose sum is σ = 104008752. Its totient is φ = 61634688.

The previous prime is 81858643. The next prime is 81858661. The reversal of 81858655 is 55685818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81858655 - 2²¹ = 79761503 is a prime.

It is a Duffinian number.

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, 481437 + ... + 481606.

It is an arithmetic number, because the mean of its divisors is an integer number (13001094).

Almost surely, 2^81858655 is an apocalyptic number.

81858655 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

81858655 is a deficient number, since it is larger than the sum of its proper divisors (22150097).

81858655 is a wasteful number, since it uses less digits than its factorization.

81858655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 963065.

The product of its digits is 384000, while the sum is 46.

The square root of 81858655 is about 9047.5773000290. The cubic root of 81858655 is about 434.1983827629.

The spelling of 81858655 in words is "eighty-one million, eight hundred fifty-eight thousand, six hundred fifty-five".