499921661 has 2 divisors, whose sum is σ = 499921662. Its totient is φ = 499921660.

The previous prime is 499921621. The next prime is 499921759. The reversal of 499921661 is 166129994.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 374616025 + 125305636 = 19355^2 + 11194^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-499921661 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (499921621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 249960830 + 249960831.

It is an arithmetic number, because the mean of its divisors is an integer number (249960831).

Almost surely, 2^499921661 is an apocalyptic number.

It is an amenable number.

499921661 is a deficient number, since it is larger than the sum of its proper divisors (1).

499921661 is an equidigital number, since it uses as much as digits as its factorization.

499921661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 209952, while the sum is 47.

The square root of 499921661 is about 22358.9279930859. The cubic root of 499921661 is about 793.6590720154.

The spelling of 499921661 in words is "four hundred ninety-nine million, nine hundred twenty-one thousand, six hundred sixty-one".