78212224 has 16 divisors (see below), whose sum is σ = 155813670. Its totient is φ = 39106048.

The previous prime is 78212209. The next prime is 78212237. The reversal of 78212224 is 42221287.

It can be written as a sum of positive squares in only one way, i.e., 60840000 + 17372224 = 7800^2 + 4168^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a super-2 number, since 2×78212224² = 12234303966052352, which contains 22 as substring.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 78212192 and 78212201.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 305389 + ... + 305644.

Almost surely, 2^78212224 is an apocalyptic number.

It is an amenable number.

78212224 is a deficient number, since it is larger than the sum of its proper divisors (77601446).

78212224 is an equidigital number, since it uses as much as digits as its factorization.

78212224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 611047 (or 611035 counting only the distinct ones).

The product of its digits is 3584, while the sum is 28.

The square root of 78212224 is about 8843.7675229508. The cubic root of 78212224 is about 427.6530218361.

The spelling of 78212224 in words is "seventy-eight million, two hundred twelve thousand, two hundred twenty-four".