81808836782 has 8 divisors (see below), whose sum is σ = 122715512352. Its totient is φ = 40903666000.

The previous prime is 81808836779. The next prime is 81808836799. The reversal of 81808836782 is 28763880818.

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

It is a super-2 number, since 2×81808836782² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 228719 + ... + 464682.

It is an arithmetic number, because the mean of its divisors is an integer number (15339439044).

Almost surely, 2^81808836782 is an apocalyptic number.

81808836782 is a deficient number, since it is larger than the sum of its proper divisors (40906675570).

81808836782 is a wasteful number, since it uses less digits than its factorization.

81808836782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 752394.

The product of its (nonzero) digits is 8257536, while the sum is 59.

The spelling of 81808836782 in words is "eighty-one billion, eight hundred eight million, eight hundred thirty-six thousand, seven hundred eighty-two".