78221894 has 4 divisors (see below), whose sum is σ = 117332844. Its totient is φ = 39110946.

The previous prime is 78221893. The next prime is 78221951. The reversal of 78221894 is 49812287.

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

It is a super-2 number, since 2×78221894² = 12237329401894472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78221893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19555472 + ... + 19555475.

It is an arithmetic number, because the mean of its divisors is an integer number (29333211).

Almost surely, 2^78221894 is an apocalyptic number.

78221894 is a deficient number, since it is larger than the sum of its proper divisors (39110950).

78221894 is a wasteful number, since it uses less digits than its factorization.

78221894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39110949.

The product of its digits is 64512, while the sum is 41.

The square root of 78221894 is about 8844.3142187509. The cubic root of 78221894 is about 427.6706458259.

The spelling of 78221894 in words is "seventy-eight million, two hundred twenty-one thousand, eight hundred ninety-four".