81955963619 has 8 divisors (see below), whose sum is σ = 85855224000. Its totient is φ = 78128249472.

The previous prime is 81955963613. The next prime is 81955963627. The reversal of 81955963619 is 91636955918.

It is a happy number.

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

It is not a de Polignac number, because 81955963619 - 2¹² = 81955959523 is a prime.

It is a super-2 number, since 2×81955963619² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81955963613) 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, 17884214 + ... + 17888795.

It is an arithmetic number, because the mean of its divisors is an integer number (10731903000).

Almost surely, 2^81955963619 is an apocalyptic number.

81955963619 is a deficient number, since it is larger than the sum of its proper divisors (3899260381).

81955963619 is a wasteful number, since it uses less digits than its factorization.

81955963619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35773117.

The product of its digits is 15746400, while the sum is 62.

The spelling of 81955963619 in words is "eighty-one billion, nine hundred fifty-five million, nine hundred sixty-three thousand, six hundred nineteen".