1999637091 has 16 divisors (see below), whose sum is σ = 2963145120. Its totient is φ = 1332767520.

The previous prime is 1999637063. The next prime is 1999637099. The reversal of 1999637091 is 1907369991.

It is not a de Polignac number, because 1999637091 - 2⁹ = 1999636579 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1999637099) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166261 + ... + 177881.

It is an arithmetic number, because the mean of its divisors is an integer number (185196570).

Almost surely, 2^1999637091 is an apocalyptic number.

1999637091 is a deficient number, since it is larger than the sum of its proper divisors (963508029).

1999637091 is a wasteful number, since it uses less digits than its factorization.

1999637091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18003 (or 17997 counting only the distinct ones).

The product of its (nonzero) digits is 826686, while the sum is 54.

The square root of 1999637091 is about 44717.3019199504. The cubic root of 1999637091 is about 1259.8448391704.

The spelling of 1999637091 in words is "one billion, nine hundred ninety-nine million, six hundred thirty-seven thousand, ninety-one".