81928155 has 16 divisors (see below), whose sum is σ = 131220000. Its totient is φ = 43650048.

The previous prime is 81928111. The next prime is 81928181. The reversal of 81928155 is 55182918.

It is not a de Polignac number, because 81928155 - 2¹⁴ = 81911771 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16549 + ... + 20921.

It is an arithmetic number, because the mean of its divisors is an integer number (8201250).

Almost surely, 2^81928155 is an apocalyptic number.

81928155 is a deficient number, since it is larger than the sum of its proper divisors (49291845).

81928155 is a wasteful number, since it uses less digits than its factorization.

81928155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5630.

The product of its digits is 28800, while the sum is 39.

The square root of 81928155 is about 9051.4172923360. The cubic root of 81928155 is about 434.3212296846.

The spelling of 81928155 in words is "eighty-one million, nine hundred twenty-eight thousand, one hundred fifty-five".