1687539991 has 2 divisors, whose sum is σ = 1687539992. Its totient is φ = 1687539990.

The previous prime is 1687539983. The next prime is 1687540109. The reversal of 1687539991 is 1999357861.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1687539991 - 2³ = 1687539983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1687534991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 843769995 + 843769996.

It is an arithmetic number, because the mean of its divisors is an integer number (843769996).

Almost surely, 2^1687539991 is an apocalyptic number.

1687539991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1687539991 is an equidigital number, since it uses as much as digits as its factorization.

1687539991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3674160, while the sum is 58.

The square root of 1687539991 is about 41079.6785649547. The cubic root of 1687539991 is about 1190.5601936064.

The spelling of 1687539991 in words is "one billion, six hundred eighty-seven million, five hundred thirty-nine thousand, nine hundred ninety-one".