660438749 has 2 divisors, whose sum is σ = 660438750. Its totient is φ = 660438748.

The previous prime is 660438731. The next prime is 660438761. The reversal of 660438749 is 947834066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 456463225 + 203975524 = 21365^2 + 14282^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-660438749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660438769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330219374 + 330219375.

It is an arithmetic number, because the mean of its divisors is an integer number (330219375).

Almost surely, 2^660438749 is an apocalyptic number.

It is an amenable number.

660438749 is a deficient number, since it is larger than the sum of its proper divisors (1).

660438749 is an equidigital number, since it uses as much as digits as its factorization.

660438749 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 870912, while the sum is 47.

The square root of 660438749 is about 25699.0028794893. The cubic root of 660438749 is about 870.8516560102.

The spelling of 660438749 in words is "six hundred sixty million, four hundred thirty-eight thousand, seven hundred forty-nine".