1659011991 has 48 divisors (see below), whose sum is σ = 2778695424. Its totient is φ = 861898752.

The previous prime is 1659011983. The next prime is 1659011993. The reversal of 1659011991 is 1991109561.

It is not a de Polignac number, because 1659011991 - 2³ = 1659011983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1659011993) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 234295 + ... + 241271.

It is an arithmetic number, because the mean of its divisors is an integer number (57889488).

Almost surely, 2^1659011991 is an apocalyptic number.

1659011991 is a deficient number, since it is larger than the sum of its proper divisors (1119683433).

1659011991 is a wasteful number, since it uses less digits than its factorization.

1659011991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7080 (or 7067 counting only the distinct ones).

The product of its (nonzero) digits is 21870, while the sum is 42.

The square root of 1659011991 is about 40730.9709066700. The cubic root of 1659011991 is about 1183.8131912385.

The spelling of 1659011991 in words is "one billion, six hundred fifty-nine million, eleven thousand, nine hundred ninety-one".