81155370 has 32 divisors (see below), whose sum is σ = 198920448. Its totient is φ = 21180608.

The previous prime is 81155353. The next prime is 81155377. The reversal of 81155370 is 7355118.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81155377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27369 + ... + 30188.

It is an arithmetic number, because the mean of its divisors is an integer number (6216264).

Almost surely, 2^81155370 is an apocalyptic number.

81155370 is an abundant number, since it is smaller than the sum of its proper divisors (117765078).

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

81155370 is a wasteful number, since it uses less digits than its factorization.

81155370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57614.

The product of its (nonzero) digits is 4200, while the sum is 30.

The square root of 81155370 is about 9008.6275314279. The cubic root of 81155370 is about 432.9513392328.

The spelling of 81155370 in words is "eighty-one million, one hundred fifty-five thousand, three hundred seventy".