820135342981 has 2 divisors, whose sum is σ = 820135342982. Its totient is φ = 820135342980.

The previous prime is 820135342967. The next prime is 820135342987. The reversal of 820135342981 is 189243531028.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 775692378756 + 44442964225 = 880734^2 + 210815^2 .

It is a cyclic number.

It is not a de Polignac number, because 820135342981 - 2⁷ = 820135342853 is a prime.

It is a super-2 number, since 2×820135342981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820135342987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410067671490 + 410067671491.

It is an arithmetic number, because the mean of its divisors is an integer number (410067671491).

Almost surely, 2^820135342981 is an apocalyptic number.

It is an amenable number.

820135342981 is a deficient number, since it is larger than the sum of its proper divisors (1).

820135342981 is an equidigital number, since it uses as much as digits as its factorization.

820135342981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 414720, while the sum is 46.

The spelling of 820135342981 in words is "eight hundred twenty billion, one hundred thirty-five million, three hundred forty-two thousand, nine hundred eighty-one".