221992649 has 2 divisors, whose sum is σ = 221992650. Its totient is φ = 221992648.

The previous prime is 221992627. The next prime is 221992679. The reversal of 221992649 is 946299122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204919225 + 17073424 = 14315^2 + 4132^2 .

It is a cyclic number.

It is not a de Polignac number, because 221992649 - 2¹² = 221988553 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (221992679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110996324 + 110996325.

It is an arithmetic number, because the mean of its divisors is an integer number (110996325).

Almost surely, 2^221992649 is an apocalyptic number.

It is an amenable number.

221992649 is a deficient number, since it is larger than the sum of its proper divisors (1).

221992649 is an equidigital number, since it uses as much as digits as its factorization.

221992649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 44.

The square root of 221992649 is about 14899.4177403011. The cubic root of 221992649 is about 605.4982112943.

The spelling of 221992649 in words is "two hundred twenty-one million, nine hundred ninety-two thousand, six hundred forty-nine".