81851904349 has 8 divisors (see below), whose sum is σ = 82668710592. Its totient is φ = 81035523840.

The previous prime is 81851904301. The next prime is 81851904359. The reversal of 81851904349 is 94340915818.

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

It is a cyclic number.

It is not a de Polignac number, because 81851904349 - 2¹⁵ = 81851871581 is a prime.

It is a super-2 number, since 2×81851904349² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81851904296 and 81851904305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81851904359) 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, 287229 + ... + 496189.

It is an arithmetic number, because the mean of its divisors is an integer number (10333588824).

Almost surely, 2^81851904349 is an apocalyptic number.

It is an amenable number.

81851904349 is a deficient number, since it is larger than the sum of its proper divisors (816806243).

81851904349 is a wasteful number, since it uses less digits than its factorization.

81851904349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212867.

The product of its (nonzero) digits is 1244160, while the sum is 52.

The spelling of 81851904349 in words is "eighty-one billion, eight hundred fifty-one million, nine hundred four thousand, three hundred forty-nine".