221993537 has 2 divisors, whose sum is σ = 221993538. Its totient is φ = 221993536.

The previous prime is 221993509. The next prime is 221993591. The reversal of 221993537 is 735399122.

It is a happy number.

221993537 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 212897281 + 9096256 = 14591^2 + 3016^2 .

It is a cyclic number.

It is not a de Polignac number, because 221993537 - 2⁸ = 221993281 is a prime.

It is a super-2 number, since 2×221993537² = 98562260939540738, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 221993494 and 221993503.

It is not a weakly prime, because it can be changed into another prime (221993137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110996768 + 110996769.

It is an arithmetic number, because the mean of its divisors is an integer number (110996769).

Almost surely, 2^221993537 is an apocalyptic number.

It is an amenable number.

221993537 is a deficient number, since it is larger than the sum of its proper divisors (1).

221993537 is an equidigital number, since it uses as much as digits as its factorization.

221993537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 102060, while the sum is 41.

The square root of 221993537 is about 14899.4475400936. The cubic root of 221993537 is about 605.4990186509.

The spelling of 221993537 in words is "two hundred twenty-one million, nine hundred ninety-three thousand, five hundred thirty-seven".