212445778 has 4 divisors (see below), whose sum is σ = 318668670. Its totient is φ = 106222888.

The previous prime is 212445769. The next prime is 212445791. The reversal of 212445778 is 877544212.

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

It can be written as a sum of positive squares in only one way, i.e., 204976489 + 7469289 = 14317^2 + 2733^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 212445778.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 53111443 + ... + 53111446.

Almost surely, 2^212445778 is an apocalyptic number.

212445778 is a deficient number, since it is larger than the sum of its proper divisors (106222892).

212445778 is a wasteful number, since it uses less digits than its factorization.

212445778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106222891.

The product of its digits is 125440, while the sum is 40.

The square root of 212445778 is about 14575.5198192037. The cubic root of 212445778 is about 596.6908363162.

The spelling of 212445778 in words is "two hundred twelve million, four hundred forty-five thousand, seven hundred seventy-eight".