81770511 has 8 divisors (see below), whose sum is σ = 109070640. Its totient is φ = 54492032.

The previous prime is 81770489. The next prime is 81770531. The reversal of 81770511 is 11507718.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 81770511 - 2¹⁰ = 81769487 is a prime.

It is a super-2 number, since 2×81770511² = 13372832938402242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81770531) 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, 8551 + ... + 15383.

It is an arithmetic number, because the mean of its divisors is an integer number (13633830).

Almost surely, 2^81770511 is an apocalyptic number.

81770511 is a deficient number, since it is larger than the sum of its proper divisors (27300129).

81770511 is a wasteful number, since it uses less digits than its factorization.

81770511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10825.

The product of its (nonzero) digits is 1960, while the sum is 30.

The square root of 81770511 is about 9042.7048497670. The cubic root of 81770511 is about 434.0424809939.

The spelling of 81770511 in words is "eighty-one million, seven hundred seventy thousand, five hundred eleven".