99661578 has 16 divisors (see below), whose sum is σ = 199552896. Its totient is φ = 33182240.

The previous prime is 99661567. The next prime is 99661589. The reversal of 99661578 is 87516699.

It is an interprime number because it is at equal distance from previous prime (99661567) and next prime (99661589).

It is a self number, because there is not a number n which added to its sum of digits gives 99661578.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3651 + ... + 14582.

It is an arithmetic number, because the mean of its divisors is an integer number (12472056).

Almost surely, 2^99661578 is an apocalyptic number.

99661578 is an abundant number, since it is smaller than the sum of its proper divisors (99891318).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

99661578 is a wasteful number, since it uses less digits than its factorization.

99661578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19149.

The product of its digits is 816480, while the sum is 51.

The square root of 99661578 is about 9983.0645595428. The cubic root of 99661578 is about 463.6346863244.

The spelling of 99661578 in words is "ninety-nine million, six hundred sixty-one thousand, five hundred seventy-eight".