1021221961 has 2 divisors, whose sum is σ = 1021221962. Its totient is φ = 1021221960.

The previous prime is 1021221959. The next prime is 1021221983. The reversal of 1021221961 is 1691221201.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 536385600 + 484836361 = 23160^2 + 22019^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021221961 - 2¹ = 1021221959 is a prime.

Together with 1021221959, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1021221911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510610980 + 510610981.

It is an arithmetic number, because the mean of its divisors is an integer number (510610981).

Almost surely, 2^1021221961 is an apocalyptic number.

It is an amenable number.

1021221961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021221961 is an equidigital number, since it uses as much as digits as its factorization.

1021221961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 1021221961 is about 31956.5636606942. The cubic root of 1021221961 is about 1007.0245274744.

The spelling of 1021221961 in words is "one billion, twenty-one million, two hundred twenty-one thousand, nine hundred sixty-one".