131220101681 has 2 divisors, whose sum is σ = 131220101682. Its totient is φ = 131220101680.

The previous prime is 131220101671. The next prime is 131220101689. The reversal of 131220101681 is 186101022131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111957160000 + 19262941681 = 334600^2 + 138791^2 .

It is an emirp because it is prime and its reverse (186101022131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 131220101681 - 2²² = 131215907377 is a prime.

It is a super-2 number, since 2×131220101681² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 131220101681.

It is not a weakly prime, because it can be changed into another prime (131220101689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65610050840 + 65610050841.

It is an arithmetic number, because the mean of its divisors is an integer number (65610050841).

Almost surely, 2^131220101681 is an apocalyptic number.

It is an amenable number.

131220101681 is a deficient number, since it is larger than the sum of its proper divisors (1).

131220101681 is an equidigital number, since it uses as much as digits as its factorization.

131220101681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 26.

The spelling of 131220101681 in words is "one hundred thirty-one billion, two hundred twenty million, one hundred one thousand, six hundred eighty-one".