1665251551 has 2 divisors, whose sum is σ = 1665251552. Its totient is φ = 1665251550.

The previous prime is 1665251527. The next prime is 1665251557. The reversal of 1665251551 is 1551525661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1665251551 - 2²³ = 1656862943 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1665251551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665251557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832625775 + 832625776.

It is an arithmetic number, because the mean of its divisors is an integer number (832625776).

Almost surely, 2^1665251551 is an apocalyptic number.

1665251551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665251551 is an equidigital number, since it uses as much as digits as its factorization.

1665251551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45000, while the sum is 37.

The square root of 1665251551 is about 40807.4938093483. The cubic root of 1665251551 is about 1185.2954454510.

The spelling of 1665251551 in words is "one billion, six hundred sixty-five million, two hundred fifty-one thousand, five hundred fifty-one".