1643156465 has 4 divisors (see below), whose sum is σ = 1971787764. Its totient is φ = 1314525168.

The previous prime is 1643156453. The next prime is 1643156483. The reversal of 1643156465 is 5646513461.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 654745744 + 988410721 = 25588^2 + 31439^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643156465 - 2¹⁰ = 1643155441 is a prime.

It is a super-4 number, since 4×1643156465⁴ (a number of 38 digits) contains 4444 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164315642 + ... + 164315651.

It is an arithmetic number, because the mean of its divisors is an integer number (492946941).

Almost surely, 2^1643156465 is an apocalyptic number.

It is an amenable number.

1643156465 is a deficient number, since it is larger than the sum of its proper divisors (328631299).

1643156465 is an equidigital number, since it uses as much as digits as its factorization.

1643156465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328631298.

The product of its digits is 259200, while the sum is 41.

The square root of 1643156465 is about 40535.8664024836. The cubic root of 1643156465 is about 1180.0297955227.

The spelling of 1643156465 in words is "one billion, six hundred forty-three million, one hundred fifty-six thousand, four hundred sixty-five".