991399102 has 16 divisors (see below), whose sum is σ = 1502991360. Its totient is φ = 490411512.

The previous prime is 991399093. The next prime is 991399109. The reversal of 991399102 is 201993199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991399109) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 316299 + ... + 319417.

It is an arithmetic number, because the mean of its divisors is an integer number (93936960).

Almost surely, 2^991399102 is an apocalyptic number.

991399102 is a deficient number, since it is larger than the sum of its proper divisors (511592258).

991399102 is a wasteful number, since it uses less digits than its factorization.

991399102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4767.

The product of its (nonzero) digits is 39366, while the sum is 43.

The square root of 991399102 is about 31486.4907857322. The cubic root of 991399102 is about 997.1247750043.

It can be divided in two parts, 99139 and 9102, that added together give a square (108241 = 329²).

The spelling of 991399102 in words is "nine hundred ninety-one million, three hundred ninety-nine thousand, one hundred two".