1643354551 has 4 divisors (see below), whose sum is σ = 1648231312. Its totient is φ = 1638477792.

The previous prime is 1643354543. The next prime is 1643354591. The reversal of 1643354551 is 1554533461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1554533461 = 13 ⋅119579497.

It is a cyclic number.

It is not a de Polignac number, because 1643354551 - 2³ = 1643354543 is a prime.

It is a super-2 number, since 2×1643354551² = 5401228360584823202, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1643354551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643354501) 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, 2437875 + ... + 2438548.

It is an arithmetic number, because the mean of its divisors is an integer number (412057828).

Almost surely, 2^1643354551 is an apocalyptic number.

1643354551 is a deficient number, since it is larger than the sum of its proper divisors (4876761).

1643354551 is an equidigital number, since it uses as much as digits as its factorization.

1643354551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4876760.

The product of its digits is 108000, while the sum is 37.

The square root of 1643354551 is about 40538.3096712233. The cubic root of 1643354551 is about 1180.0772119829.

The spelling of 1643354551 in words is "one billion, six hundred forty-three million, three hundred fifty-four thousand, five hundred fifty-one".