221620051 has 2 divisors, whose sum is σ = 221620052. Its totient is φ = 221620050.

The previous prime is 221620033. The next prime is 221620073. The reversal of 221620051 is 150026122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221620051 - 2⁹ = 221619539 is a prime.

It is not a weakly prime, because it can be changed into another prime (221620081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110810025 + 110810026.

It is an arithmetic number, because the mean of its divisors is an integer number (110810026).

Almost surely, 2^221620051 is an apocalyptic number.

221620051 is a deficient number, since it is larger than the sum of its proper divisors (1).

221620051 is an equidigital number, since it uses as much as digits as its factorization.

221620051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 221620051 is about 14886.9087120194. The cubic root of 221620051 is about 605.1592604881.

Adding to 221620051 its reverse (150026122), we get a palindrome (371646173).

The spelling of 221620051 in words is "two hundred twenty-one million, six hundred twenty thousand, fifty-one".