1100021861 has 2 divisors, whose sum is σ = 1100021862. Its totient is φ = 1100021860.

The previous prime is 1100021821. The next prime is 1100021869. The reversal of 1100021861 is 1681200011.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 926045761 + 173976100 = 30431^2 + 13190^2 .

It is a cyclic number.

It is not a de Polignac number, because 1100021861 - 2¹⁴ = 1100005477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1100021869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 550010930 + 550010931.

It is an arithmetic number, because the mean of its divisors is an integer number (550010931).

Almost surely, 2^1100021861 is an apocalyptic number.

It is an amenable number.

1100021861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1100021861 is an equidigital number, since it uses as much as digits as its factorization.

1100021861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 20.

The square root of 1100021861 is about 33166.5774688918. The cubic root of 1100021861 is about 1032.2869537976.

Adding to 1100021861 its reverse (1681200011), we get a palindrome (2781221872).

The spelling of 1100021861 in words is "one billion, one hundred million, twenty-one thousand, eight hundred sixty-one".