1221971 has 2 divisors, whose sum is σ = 1221972. Its totient is φ = 1221970.

The previous prime is 1221959. The next prime is 1222003. The reversal of 1221971 is 1791221.

It is a weak prime.

It is an emirp because it is prime and its reverse (1791221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221971 - 2⁶ = 1221907 is a prime.

It is not a weakly prime, because it can be changed into another prime (1241971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610985 + 610986.

It is an arithmetic number, because the mean of its divisors is an integer number (610986).

2^1221971 is an apocalyptic number.

1221971 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221971 is an equidigital number, since it uses as much as digits as its factorization.

1221971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 252, while the sum is 23.

The square root of 1221971 is about 1105.4279714210. The cubic root of 1221971 is about 106.9104850079.

The spelling of 1221971 in words is "one million, two hundred twenty-one thousand, nine hundred seventy-one".