99981597 has 4 divisors (see below), whose sum is σ = 133308800. Its totient is φ = 66654396.

The previous prime is 99981593. The next prime is 99981599. The reversal of 99981597 is 79518999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 99981597 - 2² = 99981593 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99981593) 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, 16663597 + ... + 16663602.

It is an arithmetic number, because the mean of its divisors is an integer number (33327200).

Almost surely, 2^99981597 is an apocalyptic number.

It is an amenable number.

99981597 is a deficient number, since it is larger than the sum of its proper divisors (33327203).

99981597 is a wasteful number, since it uses less digits than its factorization.

99981597 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33327202.

The product of its digits is 1837080, while the sum is 57.

The square root of 99981597 is about 9999.0798076623. The cubic root of 99981597 is about 464.1304085614.

The spelling of 99981597 in words is "ninety-nine million, nine hundred eighty-one thousand, five hundred ninety-seven".