81690008374 has 16 divisors (see below), whose sum is σ = 132024649680. Its totient is φ = 37684833120.

The previous prime is 81690008371. The next prime is 81690008377. The reversal of 81690008374 is 47380009618.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81690008371) and next prime (81690008377).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81690008371) 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, 705492 + ... + 813079.

It is an arithmetic number, because the mean of its divisors is an integer number (8251540605).

Almost surely, 2^81690008374 is an apocalyptic number.

81690008374 is a deficient number, since it is larger than the sum of its proper divisors (50334641306).

81690008374 is a wasteful number, since it uses less digits than its factorization.

81690008374 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1520655.

The product of its (nonzero) digits is 290304, while the sum is 46.

The spelling of 81690008374 in words is "eighty-one billion, six hundred ninety million, eight thousand, three hundred seventy-four".