1210821641 has 2 divisors, whose sum is σ = 1210821642. Its totient is φ = 1210821640.

The previous prime is 1210821631. The next prime is 1210821713. The reversal of 1210821641 is 1461280121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1210761616 + 60025 = 34796^2 + 245^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1210821641 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1210821641.

It is not a weakly prime, because it can be changed into another prime (1210821611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605410820 + 605410821.

It is an arithmetic number, because the mean of its divisors is an integer number (605410821).

Almost surely, 2^1210821641 is an apocalyptic number.

It is an amenable number.

1210821641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1210821641 is an equidigital number, since it uses as much as digits as its factorization.

1210821641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 1210821641 is about 34796.8625166120. The cubic root of 1210821641 is about 1065.8433784706.

The spelling of 1210821641 in words is "one billion, two hundred ten million, eight hundred twenty-one thousand, six hundred forty-one".