222915821 has 2 divisors, whose sum is σ = 222915822. Its totient is φ = 222915820.

The previous prime is 222915773. The next prime is 222915871. The reversal of 222915821 is 128519222.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 208369225 + 14546596 = 14435^2 + 3814^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-222915821 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (222915871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 111457910 + 111457911.

It is an arithmetic number, because the mean of its divisors is an integer number (111457911).

Almost surely, 2^222915821 is an apocalyptic number.

It is an amenable number.

222915821 is a deficient number, since it is larger than the sum of its proper divisors (1).

222915821 is an equidigital number, since it uses as much as digits as its factorization.

222915821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 32.

The square root of 222915821 is about 14930.3657356409. The cubic root of 222915821 is about 606.3363860887.

The spelling of 222915821 in words is "two hundred twenty-two million, nine hundred fifteen thousand, eight hundred twenty-one".