991986135 has 48 divisors (see below), whose sum is σ = 1889306496. Its totient is φ = 442919232.

The previous prime is 991986133. The next prime is 991986139. The reversal of 991986135 is 531689199.

It is a happy number.

It is not a de Polignac number, because 991986135 - 2¹ = 991986133 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991986133) 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, 15912 + ... + 47298.

It is an arithmetic number, because the mean of its divisors is an integer number (39360552).

Almost surely, 2^991986135 is an apocalyptic number.

991986135 is a deficient number, since it is larger than the sum of its proper divisors (897320361).

991986135 is a wasteful number, since it uses less digits than its factorization.

991986135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31452 (or 31445 counting only the distinct ones).

The product of its digits is 524880, while the sum is 51.

The square root of 991986135 is about 31495.8113881830. The cubic root of 991986135 is about 997.3215439450.

The spelling of 991986135 in words is "nine hundred ninety-one million, nine hundred eighty-six thousand, one hundred thirty-five".