99138921 has 8 divisors (see below), whose sum is σ = 151068864. Its totient is φ = 56650800.

The previous prime is 99138913. The next prime is 99138929. The reversal of 99138921 is 12983199.

It is an interprime number because it is at equal distance from previous prime (99138913) and next prime (99138929).

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

It is not a de Polignac number, because 99138921 - 2³ = 99138913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (99138929) 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, 2360430 + ... + 2360471.

It is an arithmetic number, because the mean of its divisors is an integer number (18883608).

Almost surely, 2^99138921 is an apocalyptic number.

It is an amenable number.

99138921 is a deficient number, since it is larger than the sum of its proper divisors (51929943).

99138921 is a wasteful number, since it uses less digits than its factorization.

99138921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4720911.

The product of its digits is 34992, while the sum is 42.

The square root of 99138921 is about 9956.8529666758. The cubic root of 99138921 is about 462.8227828071.

The spelling of 99138921 in words is "ninety-nine million, one hundred thirty-eight thousand, nine hundred twenty-one".