221939749 has 2 divisors, whose sum is σ = 221939750. Its totient is φ = 221939748.

The previous prime is 221939713. The next prime is 221939789. The reversal of 221939749 is 947939122.

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., 113571649 + 108368100 = 10657^2 + 10410^2 .

It is a cyclic number.

It is not a de Polignac number, because 221939749 - 2¹⁵ = 221906981 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221939699 and 221939708.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221939789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110969874 + 110969875.

It is an arithmetic number, because the mean of its divisors is an integer number (110969875).

Almost surely, 2^221939749 is an apocalyptic number.

It is an amenable number.

221939749 is a deficient number, since it is larger than the sum of its proper divisors (1).

221939749 is an equidigital number, since it uses as much as digits as its factorization.

221939749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 46.

The square root of 221939749 is about 14897.6423973728. The cubic root of 221939749 is about 605.4501115034.

The spelling of 221939749 in words is "two hundred twenty-one million, nine hundred thirty-nine thousand, seven hundred forty-nine".