99979897 has 4 divisors (see below), whose sum is σ = 100012276. Its totient is φ = 99947520.

The previous prime is 99979871. The next prime is 99979903. The reversal of 99979897 is 79897999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79897999 = 43 ⋅1858093.

It can be written as a sum of positive squares in 2 ways, for example, as 29822521 + 70157376 = 5461^2 + 8376^2 .

It is a cyclic number.

It is not a de Polignac number, because 99979897 - 2¹⁵ = 99947129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99971897) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11004 + ... + 17917.

It is an arithmetic number, because the mean of its divisors is an integer number (25003069).

Almost surely, 2^99979897 is an apocalyptic number.

It is an amenable number.

99979897 is a deficient number, since it is larger than the sum of its proper divisors (32379).

99979897 is a wasteful number, since it uses less digits than its factorization.

99979897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32378.

The product of its digits is 23147208, while the sum is 67.

The square root of 99979897 is about 9998.9947994786. The cubic root of 99979897 is about 464.1277779900.

The spelling of 99979897 in words is "ninety-nine million, nine hundred seventy-nine thousand, eight hundred ninety-seven".