663554945391 has 32 divisors (see below), whose sum is σ = 1021093731840. Its totient is φ = 380031087744.

The previous prime is 663554945359. The next prime is 663554945407. The reversal of 663554945391 is 193549455366.

It is not a de Polignac number, because 663554945391 - 2⁵ = 663554945359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663554945311) 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, 9963421 + ... + 10029798.

It is an arithmetic number, because the mean of its divisors is an integer number (31909179120).

Almost surely, 2^663554945391 is an apocalyptic number.

663554945391 is a deficient number, since it is larger than the sum of its proper divisors (357538786449).

663554945391 is a wasteful number, since it uses less digits than its factorization.

663554945391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19993295.

The product of its digits is 52488000, while the sum is 60.

The spelling of 663554945391 in words is "six hundred sixty-three billion, five hundred fifty-four million, nine hundred forty-five thousand, three hundred ninety-one".