99778541 has 2 divisors, whose sum is σ = 99778542. Its totient is φ = 99778540.

The previous prime is 99778537. The next prime is 99778561. The reversal of 99778541 is 14587799.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98922916 + 855625 = 9946^2 + 925^2 .

It is an emirp because it is prime and its reverse (14587799) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99778541 - 2² = 99778537 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 99778541.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99778561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49889270 + 49889271.

It is an arithmetic number, because the mean of its divisors is an integer number (49889271).

Almost surely, 2^99778541 is an apocalyptic number.

It is an amenable number.

99778541 is a deficient number, since it is larger than the sum of its proper divisors (1).

99778541 is an equidigital number, since it uses as much as digits as its factorization.

99778541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 635040, while the sum is 50.

The square root of 99778541 is about 9988.9209126912. The cubic root of 99778541 is about 463.8159895730.

The spelling of 99778541 in words is "ninety-nine million, seven hundred seventy-eight thousand, five hundred forty-one".