81770145 has 8 divisors (see below), whose sum is σ = 130832256. Its totient is φ = 43610736.

The previous prime is 81770137. The next prime is 81770159. The reversal of 81770145 is 54107718.

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

It is not a de Polignac number, because 81770145 - 2³ = 81770137 is a prime.

It is a super-2 number, since 2×81770145² = 13372713226642050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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, 2725657 + ... + 2725686.

It is an arithmetic number, because the mean of its divisors is an integer number (16354032).

Almost surely, 2^81770145 is an apocalyptic number.

It is an amenable number.

81770145 is a deficient number, since it is larger than the sum of its proper divisors (49062111).

81770145 is a wasteful number, since it uses less digits than its factorization.

81770145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5451351.

The product of its (nonzero) digits is 7840, while the sum is 33.

The square root of 81770145 is about 9042.6846124367. The cubic root of 81770145 is about 434.0418334101.

The spelling of 81770145 in words is "eighty-one million, seven hundred seventy thousand, one hundred forty-five".