661412531970811 has 2 divisors, whose sum is σ = 661412531970812. Its totient is φ = 661412531970810.

The previous prime is 661412531970787. The next prime is 661412531970991. The reversal of 661412531970811 is 118079135214166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661412531970811 - 2¹⁹ = 661412531446523 is a prime.

It is not a weakly prime, because it can be changed into another prime (661412531770811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330706265985405 + 330706265985406.

It is an arithmetic number, because the mean of its divisors is an integer number (330706265985406).

It is a 1-persistent number, because it is pandigital, but 2⋅661412531970811 = 1322825063941622 is not.

Almost surely, 2^{661412531970811} is an apocalyptic number.

661412531970811 is a deficient number, since it is larger than the sum of its proper divisors (1).

661412531970811 is an equidigital number, since it uses as much as digits as its factorization.

661412531970811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2177280, while the sum is 55.

The spelling of 661412531970811 in words is "six hundred sixty-one trillion, four hundred twelve billion, five hundred thirty-one million, nine hundred seventy thousand, eight hundred eleven".