221649331 has 2 divisors, whose sum is σ = 221649332. Its totient is φ = 221649330.

The previous prime is 221649301. The next prime is 221649341. The reversal of 221649331 is 133946122.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221649331 is a prime.

It is a super-2 number, since 2×221649331² = 98256851865495122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221649293 and 221649302.

It is not a weakly prime, because it can be changed into another prime (221649301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110824665 + 110824666.

It is an arithmetic number, because the mean of its divisors is an integer number (110824666).

Almost surely, 2^221649331 is an apocalyptic number.

221649331 is a deficient number, since it is larger than the sum of its proper divisors (1).

221649331 is an equidigital number, since it uses as much as digits as its factorization.

221649331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 31.

The square root of 221649331 is about 14887.8920939131. The cubic root of 221649331 is about 605.1859101268.

The spelling of 221649331 in words is "two hundred twenty-one million, six hundred forty-nine thousand, three hundred thirty-one".