1200021101 has 2 divisors, whose sum is σ = 1200021102. Its totient is φ = 1200021100.

The previous prime is 1200021079. The next prime is 1200021107. The reversal of 1200021101 is 1011200021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1037484100 + 162537001 = 32210^2 + 12749^2 .

It is a cyclic number.

It is not a de Polignac number, because 1200021101 - 2¹⁸ = 1199758957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1200021107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 600010550 + 600010551.

It is an arithmetic number, because the mean of its divisors is an integer number (600010551).

Almost surely, 2^1200021101 is an apocalyptic number.

It is an amenable number.

1200021101 is a deficient number, since it is larger than the sum of its proper divisors (1).

1200021101 is an equidigital number, since it uses as much as digits as its factorization.

1200021101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 1200021101 is about 34641.3207167394. The cubic root of 1200021101 is about 1062.6647978012.

Adding to 1200021101 its reverse (1011200021), we get a palindrome (2211221122).

It can be divided in two parts, 1200021 and 101, that multiplied together give a palindrome (121202121).

The spelling of 1200021101 in words is "one billion, two hundred million, twenty-one thousand, one hundred one".