1644612087391 has 32 divisors (see below), whose sum is σ = 2027248888448. Its totient is φ = 1299233364480.

The previous prime is 1644612087373. The next prime is 1644612087401. The reversal of 1644612087391 is 1937802164461.

It is a cyclic number.

It is not a de Polignac number, because 1644612087391 - 2⁹ = 1644612086879 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644612087301) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 182466601 + ... + 182475613.

It is an arithmetic number, because the mean of its divisors is an integer number (63351527764).

Almost surely, 2^{1644612087391} is an apocalyptic number.

1644612087391 is a deficient number, since it is larger than the sum of its proper divisors (382636801057).

1644612087391 is a wasteful number, since it uses less digits than its factorization.

1644612087391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11891.

The product of its (nonzero) digits is 1741824, while the sum is 52.

The spelling of 1644612087391 in words is "one trillion, six hundred forty-four billion, six hundred twelve million, eighty-seven thousand, three hundred ninety-one".