221125631 has 2 divisors, whose sum is σ = 221125632. Its totient is φ = 221125630.

The previous prime is 221125607. The next prime is 221125643. The reversal of 221125631 is 136521122.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221125631 is a prime.

It is a super-2 number, since 2×221125631² = 97793089370296322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 221125597 and 221125606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221125831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110562815 + 110562816.

It is an arithmetic number, because the mean of its divisors is an integer number (110562816).

Almost surely, 2^221125631 is an apocalyptic number.

221125631 is a deficient number, since it is larger than the sum of its proper divisors (1).

221125631 is an equidigital number, since it uses as much as digits as its factorization.

221125631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 23.

The square root of 221125631 is about 14870.2935747752. The cubic root of 221125631 is about 604.7089016914.

Adding to 221125631 its reverse (136521122), we get a palindrome (357646753).

The spelling of 221125631 in words is "two hundred twenty-one million, one hundred twenty-five thousand, six hundred thirty-one".