1999971653 has 2 divisors, whose sum is σ = 1999971654. Its totient is φ = 1999971652.

The previous prime is 1999971607. The next prime is 1999971671. The reversal of 1999971653 is 3561799991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1518037444 + 481934209 = 38962^2 + 21953^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999971653 - 2¹⁰ = 1999970629 is a prime.

It is a super-2 number, since 2×1999971653² = 7999773225607104818, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1999971592 and 1999971601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999971553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999985826 + 999985827.

It is an arithmetic number, because the mean of its divisors is an integer number (999985827).

Almost surely, 2^1999971653 is an apocalyptic number.

It is an amenable number.

1999971653 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999971653 is an equidigital number, since it uses as much as digits as its factorization.

1999971653 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4133430, while the sum is 59.

The square root of 1999971653 is about 44721.0426197780. The cubic root of 1999971653 is about 1259.9150973698.

The spelling of 1999971653 in words is "one billion, nine hundred ninety-nine million, nine hundred seventy-one thousand, six hundred fifty-three".