1643749097 has 4 divisors (see below), whose sum is σ = 1643832276. Its totient is φ = 1643665920.

The previous prime is 1643749031. The next prime is 1643749117. The reversal of 1643749097 is 7909473461.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 290907136 + 1352841961 = 17056^2 + 36781^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643749097 - 2¹⁸ = 1643486953 is a prime.

It is a super-2 number, since 2×1643749097² = 5403822187776630818, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1643749007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6893 + ... + 57749.

It is an arithmetic number, because the mean of its divisors is an integer number (410958069).

Almost surely, 2^1643749097 is an apocalyptic number.

It is an amenable number.

1643749097 is a deficient number, since it is larger than the sum of its proper divisors (83179).

1643749097 is an equidigital number, since it uses as much as digits as its factorization.

1643749097 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83178.

The product of its (nonzero) digits is 1143072, while the sum is 50.

The square root of 1643749097 is about 40543.1757142925. The cubic root of 1643749097 is about 1180.1716443312.

The spelling of 1643749097 in words is "one billion, six hundred forty-three million, seven hundred forty-nine thousand, ninety-seven".