81775715 has 16 divisors (see below), whose sum is σ = 118053120. Its totient is φ = 53123040.

The previous prime is 81775699. The next prime is 81775739. The reversal of 81775715 is 51757718.

It is a happy number.

It is not a de Polignac number, because 81775715 - 2⁴ = 81775699 is a prime.

It is a super-2 number, since 2×81775715² = 13374535127522450, which contains 22 as substring.

It is a plaindrome in base 12.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60821 + ... + 62150.

It is an arithmetic number, because the mean of its divisors is an integer number (7378320).

Almost surely, 2^81775715 is an apocalyptic number.

81775715 is a deficient number, since it is larger than the sum of its proper divisors (36277405).

81775715 is a wasteful number, since it uses less digits than its factorization.

81775715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123002.

The product of its digits is 68600, while the sum is 41.

The square root of 81775715 is about 9042.9925909513. The cubic root of 81775715 is about 434.0516885071.

The spelling of 81775715 in words is "eighty-one million, seven hundred seventy-five thousand, seven hundred fifteen".