666451553 has 2 divisors, whose sum is σ = 666451554. Its totient is φ = 666451552.

The previous prime is 666451507. The next prime is 666451559. The reversal of 666451553 is 355154666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 351637504 + 314814049 = 18752^2 + 17743^2 .

It is a cyclic number.

It is not a de Polignac number, because 666451553 - 2¹⁸ = 666189409 is a prime.

It is a super-2 number, since 2×666451553² = 888315344992223618, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 666451553.

It is not a weakly prime, because it can be changed into another prime (666451559) 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, 333225776 + 333225777.

It is an arithmetic number, because the mean of its divisors is an integer number (333225777).

Almost surely, 2^666451553 is an apocalyptic number.

It is an amenable number.

666451553 is a deficient number, since it is larger than the sum of its proper divisors (1).

666451553 is an equidigital number, since it uses as much as digits as its factorization.

666451553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 324000, while the sum is 41.

The square root of 666451553 is about 25815.7229803854. The cubic root of 666451553 is about 873.4864950800.

The spelling of 666451553 in words is "six hundred sixty-six million, four hundred fifty-one thousand, five hundred fifty-three".