1661151565631 has 2 divisors, whose sum is σ = 1661151565632. Its totient is φ = 1661151565630.

The previous prime is 1661151565607. The next prime is 1661151565709. The reversal of 1661151565631 is 1365651511661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1661151565631 - 2¹⁰ = 1661151564607 is a prime.

It is a super-2 number, since 2×1661151565631² (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 (1661151565531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830575782815 + 830575782816.

It is an arithmetic number, because the mean of its divisors is an integer number (830575782816).

Almost surely, 2^{1661151565631} is an apocalyptic number.

1661151565631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661151565631 is an equidigital number, since it uses as much as digits as its factorization.

1661151565631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 486000, while the sum is 47.

The spelling of 1661151565631 in words is "one trillion, six hundred sixty-one billion, one hundred fifty-one million, five hundred sixty-five thousand, six hundred thirty-one".