21222445778 has 8 divisors (see below), whose sum is σ = 32047317900. Its totient is φ = 10540006480.

The previous prime is 21222445757. The next prime is 21222445799. The reversal of 21222445778 is 87754422212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21222445757) and next prime (21222445799).

It can be written as a sum of positive squares in 2 ways, for example, as 18552346849 + 2670098929 = 136207^2 + 51673^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35607833 + ... + 35608428.

Almost surely, 2^21222445778 is an apocalyptic number.

21222445778 is a deficient number, since it is larger than the sum of its proper divisors (10824872122).

21222445778 is a wasteful number, since it uses less digits than its factorization.

21222445778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71216412.

The product of its digits is 501760, while the sum is 44.

The spelling of 21222445778 in words is "twenty-one billion, two hundred twenty-two million, four hundred forty-five thousand, seven hundred seventy-eight".