99440639 has 4 divisors (see below), whose sum is σ = 101753256. Its totient is φ = 97128024.

The previous prime is 99440609. The next prime is 99440641. The reversal of 99440639 is 93604499.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99440639 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 99440639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99440609) 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, 1156244 + ... + 1156329.

It is an arithmetic number, because the mean of its divisors is an integer number (25438314).

Almost surely, 2^99440639 is an apocalyptic number.

99440639 is a deficient number, since it is larger than the sum of its proper divisors (2312617).

99440639 is a wasteful number, since it uses less digits than its factorization.

99440639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2312616.

The product of its (nonzero) digits is 209952, while the sum is 44.

The square root of 99440639 is about 9971.9927296404. The cubic root of 99440639 is about 463.2918234239.

The spelling of 99440639 in words is "ninety-nine million, four hundred forty thousand, six hundred thirty-nine".