781549196161 has 4 divisors (see below), whose sum is σ = 822683364400. Its totient is φ = 740415027924.

The previous prime is 781549196107. The next prime is 781549196167. The reversal of 781549196161 is 161691945187.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-781549196161 is a prime.

It is a super-2 number, since 2×781549196161² (a number of 25 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 = 781549196096 and 781549196105.

It is not an unprimeable number, because it can be changed into a prime (781549196167) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20567084091 + ... + 20567084128.

It is an arithmetic number, because the mean of its divisors is an integer number (205670841100).

Almost surely, 2^781549196161 is an apocalyptic number.

It is an amenable number.

781549196161 is a deficient number, since it is larger than the sum of its proper divisors (41134168239).

781549196161 is a wasteful number, since it uses less digits than its factorization.

781549196161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41134168238.

The product of its digits is 3265920, while the sum is 58.

The spelling of 781549196161 in words is "seven hundred eighty-one billion, five hundred forty-nine million, one hundred ninety-six thousand, one hundred sixty-one".