99997581 has 8 divisors (see below), whose sum is σ = 134553760. Its totient is φ = 66053232.

The previous prime is 99997571. The next prime is 99997609. The reversal of 99997581 is 18579999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 99997581 - 2⁹ = 99997069 is a prime.

It is a super-2 number, since 2×99997581² = 19999032411703122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99997511) 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, 152575 + ... + 153228.

It is an arithmetic number, because the mean of its divisors is an integer number (16819220).

Almost surely, 2^99997581 is an apocalyptic number.

It is an amenable number.

99997581 is a deficient number, since it is larger than the sum of its proper divisors (34556179).

99997581 is a wasteful number, since it uses less digits than its factorization.

99997581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305915.

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

The square root of 99997581 is about 9999.8790492685. The cubic root of 99997581 is about 464.1551406633.

The spelling of 99997581 in words is "ninety-nine million, nine hundred ninety-seven thousand, five hundred eighty-one".