99851778 has 80 divisors (see below), whose sum is σ = 255218040. Its totient is φ = 28905984.

The previous prime is 99851747. The next prime is 99851779. The reversal of 99851778 is 87715899.

It can be written as a sum of positive squares in 4 ways, for example, as 86434209 + 13417569 = 9297^2 + 3663^2 .

It is a super-2 number, since 2×99851778² = 19940755139522568, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a zygodrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (99851779) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 34408 + ... + 37196.

Almost surely, 2^99851778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99851778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127609020).

99851778 is an abundant number, since it is smaller than the sum of its proper divisors (155366262).

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

99851778 is a wasteful number, since it uses less digits than its factorization.

99851778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2833 (or 2824 counting only the distinct ones).

The product of its digits is 1270080, while the sum is 54.

The square root of 99851778 is about 9992.5861517427. The cubic root of 99851778 is about 463.9294414361.

The spelling of 99851778 in words is "ninety-nine million, eight hundred fifty-one thousand, seven hundred seventy-eight".