81699953590 has 32 divisors (see below), whose sum is σ = 148616519040. Its totient is φ = 32335814784.

The previous prime is 81699953581. The next prime is 81699953597. The reversal of 81699953590 is 9535999618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81699953597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 266364 + ... + 484096.

It is an arithmetic number, because the mean of its divisors is an integer number (4644266220).

Almost surely, 2^81699953590 is an apocalyptic number.

81699953590 is a deficient number, since it is larger than the sum of its proper divisors (66916565450).

81699953590 is a wasteful number, since it uses less digits than its factorization.

81699953590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218136.

The product of its (nonzero) digits is 23619600, while the sum is 64.

The spelling of 81699953590 in words is "eighty-one billion, six hundred ninety-nine million, nine hundred fifty-three thousand, five hundred ninety".