81219801601 has 8 divisors (see below), whose sum is σ = 83424348800. Its totient is φ = 79015750128.

The previous prime is 81219801599. The next prime is 81219801653. The reversal of 81219801601 is 10610891218.

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 81219801601 - 2¹ = 81219801599 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81219801301) 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, 221050 + ... + 459676.

It is an arithmetic number, because the mean of its divisors is an integer number (10428043600).

Almost surely, 2^81219801601 is an apocalyptic number.

It is an amenable number.

81219801601 is a deficient number, since it is larger than the sum of its proper divisors (2204547199).

81219801601 is a wasteful number, since it uses less digits than its factorization.

81219801601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247863.

The product of its (nonzero) digits is 6912, while the sum is 37.

The spelling of 81219801601 in words is "eighty-one billion, two hundred nineteen million, eight hundred one thousand, six hundred one".