97919991 has 24 divisors (see below), whose sum is σ = 155203776. Its totient is φ = 59117760.

The previous prime is 97919989. The next prime is 97920001. The reversal of 97919991 is 19991979.

It is not a de Polignac number, because 97919991 - 2¹ = 97919989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (97919911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1695 + ... + 14096.

It is an arithmetic number, because the mean of its divisors is an integer number (6466824).

Almost surely, 2^97919991 is an apocalyptic number.

97919991 is a deficient number, since it is larger than the sum of its proper divisors (57283785).

97919991 is a wasteful number, since it uses less digits than its factorization.

97919991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15863 (or 15860 counting only the distinct ones).

The product of its digits is 413343, while the sum is 54.

The square root of 97919991 is about 9895.4530467281. The cubic root of 97919991 is about 460.9181268832.

The spelling of 97919991 in words is "ninety-seven million, nine hundred nineteen thousand, nine hundred ninety-one".