220721951 has 2 divisors, whose sum is σ = 220721952. Its totient is φ = 220721950.

The previous prime is 220721939. The next prime is 220721957. The reversal of 220721951 is 159127022.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-220721951 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220721957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110360975 + 110360976.

It is an arithmetic number, because the mean of its divisors is an integer number (110360976).

Almost surely, 2^220721951 is an apocalyptic number.

220721951 is a deficient number, since it is larger than the sum of its proper divisors (1).

220721951 is an equidigital number, since it uses as much as digits as its factorization.

220721951 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 220721951 is about 14856.7140041128. The cubic root of 220721951 is about 604.3406983538.

Adding to 220721951 its reverse (159127022), we get a palindrome (379848973).

The spelling of 220721951 in words is "two hundred twenty million, seven hundred twenty-one thousand, nine hundred fifty-one".