1221110251 has 2 divisors, whose sum is σ = 1221110252. Its totient is φ = 1221110250.

The previous prime is 1221110249. The next prime is 1221110269. The reversal of 1221110251 is 1520111221.

It is a weak prime.

It is an emirp because it is prime and its reverse (1520111221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221110251 - 2¹ = 1221110249 is a prime.

It is a super-2 number, since 2×1221110251² = 2982220490194566002, which contains 22 as substring.

Together with 1221110249, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1221110281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610555125 + 610555126.

It is an arithmetic number, because the mean of its divisors is an integer number (610555126).

Almost surely, 2^1221110251 is an apocalyptic number.

1221110251 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221110251 is an equidigital number, since it uses as much as digits as its factorization.

1221110251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 16.

The square root of 1221110251 is about 34944.3879757537. The cubic root of 1221110251 is about 1068.8537674471.

Adding to 1221110251 its reverse (1520111221), we get a palindrome (2741221472).

The spelling of 1221110251 in words is "one billion, two hundred twenty-one million, one hundred ten thousand, two hundred fifty-one".