1662751561 has 2 divisors, whose sum is σ = 1662751562. Its totient is φ = 1662751560.

The previous prime is 1662751523. The next prime is 1662751591. The reversal of 1662751561 is 1651572661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 859369225 + 803382336 = 29315^2 + 28344^2 .

It is a cyclic number.

It is not a de Polignac number, because 1662751561 - 2²³ = 1654362953 is a prime.

It is not a weakly prime, because it can be changed into another prime (1662751591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 831375780 + 831375781.

It is an arithmetic number, because the mean of its divisors is an integer number (831375781).

Almost surely, 2^1662751561 is an apocalyptic number.

It is an amenable number.

1662751561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1662751561 is an equidigital number, since it uses as much as digits as its factorization.

1662751561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 75600, while the sum is 40.

The square root of 1662751561 is about 40776.8507979711. The cubic root of 1662751561 is about 1184.7019994011.

The spelling of 1662751561 in words is "one billion, six hundred sixty-two million, seven hundred fifty-one thousand, five hundred sixty-one".