61477809181 has 2 divisors, whose sum is σ = 61477809182. Its totient is φ = 61477809180.

The previous prime is 61477809179. The next prime is 61477809229. The reversal of 61477809181 is 18190877416.

It is a happy number.

61477809181 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53747003556 + 7730805625 = 231834^2 + 87925^2 .

It is a cyclic number.

It is not a de Polignac number, because 61477809181 - 2¹ = 61477809179 is a prime.

It is a super-2 number, since 2×61477809181² (a number of 22 digits) contains 22 as substring.

Together with 61477809179, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61477809161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30738904590 + 30738904591.

It is an arithmetic number, because the mean of its divisors is an integer number (30738904591).

Almost surely, 2^61477809181 is an apocalyptic number.

It is an amenable number.

61477809181 is a deficient number, since it is larger than the sum of its proper divisors (1).

61477809181 is an equidigital number, since it uses as much as digits as its factorization.

61477809181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 677376, while the sum is 52.

The spelling of 61477809181 in words is "sixty-one billion, four hundred seventy-seven million, eight hundred nine thousand, one hundred eighty-one".