61400818981 has 2 divisors, whose sum is σ = 61400818982. Its totient is φ = 61400818980.

The previous prime is 61400818939. The next prime is 61400818993. The reversal of 61400818981 is 18981800416.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44971988356 + 16428830625 = 212066^2 + 128175^2 .

It is a cyclic number.

It is not a de Polignac number, because 61400818981 - 2¹¹ = 61400816933 is a prime.

It is a super-2 number, since 2×61400818981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61400818781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30700409490 + 30700409491.

It is an arithmetic number, because the mean of its divisors is an integer number (30700409491).

Almost surely, 2^61400818981 is an apocalyptic number.

It is an amenable number.

61400818981 is a deficient number, since it is larger than the sum of its proper divisors (1).

61400818981 is an equidigital number, since it uses as much as digits as its factorization.

61400818981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 110592, while the sum is 46.

The spelling of 61400818981 in words is "sixty-one billion, four hundred million, eight hundred eighteen thousand, nine hundred eighty-one".