100000999581 has 32 divisors (see below), whose sum is σ = 159131394048. Its totient is φ = 54616446720.

The previous prime is 100000999547. The next prime is 100000999583. The reversal of 100000999581 is 185999000001.

It is not a de Polignac number, because 100000999581 - 2⁶ = 100000999517 is a prime.

It is a super-2 number, since 2×100000999581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100000999583) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 546636 + ... + 706266.

It is an arithmetic number, because the mean of its divisors is an integer number (4972856064).

Almost surely, 2^100000999581 is an apocalyptic number.

It is an amenable number.

100000999581 is a deficient number, since it is larger than the sum of its proper divisors (59130394467).

100000999581 is a wasteful number, since it uses less digits than its factorization.

100000999581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160961.

The product of its (nonzero) digits is 29160, while the sum is 42.

Adding to 100000999581 its reverse (185999000001), we get a palindrome (285999999582).

The spelling of 100000999581 in words is "one hundred billion, nine hundred ninety-nine thousand, five hundred eighty-one".