1603999961 has 2 divisors, whose sum is σ = 1603999962. Its totient is φ = 1603999960.

The previous prime is 1603999927. The next prime is 1604000023. The reversal of 1603999961 is 1699993061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1586827225 + 17172736 = 39835^2 + 4144^2 .

It is a cyclic number.

It is not a de Polignac number, because 1603999961 - 2²² = 1599805657 is a prime.

It is not a weakly prime, because it can be changed into another prime (1603992961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 801999980 + 801999981.

It is an arithmetic number, because the mean of its divisors is an integer number (801999981).

Almost surely, 2^1603999961 is an apocalyptic number.

It is an amenable number.

1603999961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1603999961 is an equidigital number, since it uses as much as digits as its factorization.

1603999961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 708588, while the sum is 53.

The square root of 1603999961 is about 40049.9683021098. The cubic root of 1603999961 is about 1170.5809472764.

The spelling of 1603999961 in words is "one billion, six hundred three million, nine hundred ninety-nine thousand, nine hundred sixty-one".