1643245120999 has 4 divisors (see below), whose sum is σ = 1696253028160. Its totient is φ = 1590237213840.

The previous prime is 1643245120997. The next prime is 1643245121071. The reversal of 1643245120999 is 9990215423461.

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

It is not a de Polignac number, because 1643245120999 - 2¹ = 1643245120997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643245120991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26503953534 + ... + 26503953595.

It is an arithmetic number, because the mean of its divisors is an integer number (424063257040).

Almost surely, 2^{1643245120999} is an apocalyptic number.

1643245120999 is a deficient number, since it is larger than the sum of its proper divisors (53007907161).

1643245120999 is an equidigital number, since it uses as much as digits as its factorization.

1643245120999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53007907160.

The product of its (nonzero) digits is 4199040, while the sum is 55.

The spelling of 1643245120999 in words is "one trillion, six hundred forty-three billion, two hundred forty-five million, one hundred twenty thousand, nine hundred ninety-nine".