99778542 has 32 divisors (see below), whose sum is σ = 215294112. Its totient is φ = 30710784.

The previous prime is 99778541. The next prime is 99778561. The reversal of 99778542 is 24587799.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99778541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3823 + ... + 14634.

It is an arithmetic number, because the mean of its divisors is an integer number (6727941).

Almost surely, 2^99778542 is an apocalyptic number.

99778542 is an abundant number, since it is smaller than the sum of its proper divisors (115515570).

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

99778542 is a wasteful number, since it uses less digits than its factorization.

99778542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18532.

The product of its digits is 1270080, while the sum is 51.

The square root of 99778542 is about 9988.9209627467. The cubic root of 99778542 is about 463.8159911225.

The spelling of 99778542 in words is "ninety-nine million, seven hundred seventy-eight thousand, five hundred forty-two".