81555310 has 8 divisors (see below), whose sum is σ = 146799576. Its totient is φ = 32622120.

The previous prime is 81555283. The next prime is 81555311. The reversal of 81555310 is 1355518.

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

It is a super-2 number, since 2×81555310² = 13302537178392200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81555311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4077756 + ... + 4077775.

It is an arithmetic number, because the mean of its divisors is an integer number (18349947).

Almost surely, 2^81555310 is an apocalyptic number.

81555310 is a deficient number, since it is larger than the sum of its proper divisors (65244266).

81555310 is a wasteful number, since it uses less digits than its factorization.

81555310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8155538.

The product of its (nonzero) digits is 3000, while the sum is 28.

The square root of 81555310 is about 9030.7978606544. The cubic root of 81555310 is about 433.6613801296.

The spelling of 81555310 in words is "eighty-one million, five hundred fifty-five thousand, three hundred ten".