81519955 has 8 divisors (see below), whose sum is σ = 106717104. Its totient is φ = 59287200.

The previous prime is 81519953. The next prime is 81519967. The reversal of 81519955 is 55991518.

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

It is not a de Polignac number, because 81519955 - 2¹ = 81519953 is a prime.

It is a super-3 number, since 3×81519955³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81519953) 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, 741036 + ... + 741145.

It is an arithmetic number, because the mean of its divisors is an integer number (13339638).

Almost surely, 2^81519955 is an apocalyptic number.

81519955 is a deficient number, since it is larger than the sum of its proper divisors (25197149).

81519955 is a wasteful number, since it uses less digits than its factorization.

81519955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1482197.

The product of its digits is 81000, while the sum is 43.

The square root of 81519955 is about 9028.8401802225. The cubic root of 81519955 is about 433.5987056323.

The spelling of 81519955 in words is "eighty-one million, five hundred nineteen thousand, nine hundred fifty-five".