1667860661 has 2 divisors, whose sum is σ = 1667860662. Its totient is φ = 1667860660.

The previous prime is 1667860637. The next prime is 1667860669. The reversal of 1667860661 is 1660687661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1203673636 + 464187025 = 34694^2 + 21545^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1667860661 is a prime.

It is a super-2 number, since 2×1667860661² = 5563518369022713842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1667860669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833930330 + 833930331.

It is an arithmetic number, because the mean of its divisors is an integer number (833930331).

Almost surely, 2^1667860661 is an apocalyptic number.

It is an amenable number.

1667860661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1667860661 is an equidigital number, since it uses as much as digits as its factorization.

1667860661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 47.

The square root of 1667860661 is about 40839.4498126505. The cubic root of 1667860661 is about 1185.9141612764.

The spelling of 1667860661 in words is "one billion, six hundred sixty-seven million, eight hundred sixty thousand, six hundred sixty-one".