1663120391 has 6 divisors (see below), whose sum is σ = 1722447792. Its totient is φ = 1605770600.

The previous prime is 1663120373. The next prime is 1663120429. The reversal of 1663120391 is 1930213661.

It is a de Polignac number, because none of the positive numbers 2^k-1663120391 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 (1663120301) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 987935 + ... + 989616.

It is an arithmetic number, because the mean of its divisors is an integer number (287074632).

Almost surely, 2^1663120391 is an apocalyptic number.

1663120391 is a deficient number, since it is larger than the sum of its proper divisors (59327401).

1663120391 is an equidigital number, since it uses as much as digits as its factorization.

1663120391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1977609 (or 1977580 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 1663120391 is about 40781.3730887031. The cubic root of 1663120391 is about 1184.7895894224.

The spelling of 1663120391 in words is "one billion, six hundred sixty-three million, one hundred twenty thousand, three hundred ninety-one".