61331100161 has 4 divisors (see below), whose sum is σ = 62171252292. Its totient is φ = 60490948032.

The previous prime is 61331100143. The next prime is 61331100241. The reversal of 61331100161 is 16100113316.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 48373603600 + 12957496561 = 219940^2 + 113831^2 .

It is a cyclic number.

It is not a de Polignac number, because 61331100161 - 2⁶ = 61331100097 is a prime.

It is a super-2 number, since 2×61331100161² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61331100361) 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, 420075956 + ... + 420076101.

It is an arithmetic number, because the mean of its divisors is an integer number (15542813073).

Almost surely, 2^61331100161 is an apocalyptic number.

It is an amenable number.

61331100161 is a deficient number, since it is larger than the sum of its proper divisors (840152131).

61331100161 is an equidigital number, since it uses as much as digits as its factorization.

61331100161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840152130.

The product of its (nonzero) digits is 324, while the sum is 23.

Adding to 61331100161 its reverse (16100113316), we get a palindrome (77431213477).

The spelling of 61331100161 in words is "sixty-one billion, three hundred thirty-one million, one hundred thousand, one hundred sixty-one".