81457777690 has 16 divisors (see below), whose sum is σ = 148480001280. Its totient is φ = 32170666320.

The previous prime is 81457777679. The next prime is 81457777697. The reversal of 81457777690 is 9677775418.

It is a super-2 number, since 2×81457777690² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81457777697) 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 7 ways as a sum of consecutive naturals, for example, 51554766 + ... + 51556345.

It is an arithmetic number, because the mean of its divisors is an integer number (9280000080).

Almost surely, 2^81457777690 is an apocalyptic number.

81457777690 is a deficient number, since it is larger than the sum of its proper divisors (67022223590).

81457777690 is a wasteful number, since it uses less digits than its factorization.

81457777690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103111197.

The product of its (nonzero) digits is 20744640, while the sum is 61.

The spelling of 81457777690 in words is "eighty-one billion, four hundred fifty-seven million, seven hundred seventy-seven thousand, six hundred ninety".