221641493 has 2 divisors, whose sum is σ = 221641494. Its totient is φ = 221641492.

The previous prime is 221641489. The next prime is 221641549. The reversal of 221641493 is 394146122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162766564 + 58874929 = 12758^2 + 7673^2 .

It is a cyclic number.

It is not a de Polignac number, because 221641493 - 2² = 221641489 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221641423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110820746 + 110820747.

It is an arithmetic number, because the mean of its divisors is an integer number (110820747).

Almost surely, 2^221641493 is an apocalyptic number.

It is an amenable number.

221641493 is a deficient number, since it is larger than the sum of its proper divisors (1).

221641493 is an equidigital number, since it uses as much as digits as its factorization.

221641493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 32.

The square root of 221641493 is about 14887.6288575448. The cubic root of 221641493 is about 605.1787764816.

The spelling of 221641493 in words is "two hundred twenty-one million, six hundred forty-one thousand, four hundred ninety-three".