1661736971 has 2 divisors, whose sum is σ = 1661736972. Its totient is φ = 1661736970.

The previous prime is 1661736919. The next prime is 1661736983. The reversal of 1661736971 is 1796371661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1661736971 - 2⁶ = 1661736907 is a prime.

It is a super-2 number, since 2×1661736971² = 5522739521576509682, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (1661736911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830868485 + 830868486.

It is an arithmetic number, because the mean of its divisors is an integer number (830868486).

Almost surely, 2^1661736971 is an apocalyptic number.

1661736971 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661736971 is an equidigital number, since it uses as much as digits as its factorization.

1661736971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 285768, while the sum is 47.

The square root of 1661736971 is about 40764.4081399448. The cubic root of 1661736971 is about 1184.4609869749.

The spelling of 1661736971 in words is "one billion, six hundred sixty-one million, seven hundred thirty-six thousand, nine hundred seventy-one".