2021121901 has 2 divisors, whose sum is σ = 2021121902. Its totient is φ = 2021121900.

The previous prime is 2021121889. The next prime is 2021121931. The reversal of 2021121901 is 1091211202.

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., 1415715876 + 605406025 = 37626^2 + 24605^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021121901 - 2¹¹ = 2021119853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2021121931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010560950 + 1010560951.

It is an arithmetic number, because the mean of its divisors is an integer number (1010560951).

Almost surely, 2^2021121901 is an apocalyptic number.

It is an amenable number.

2021121901 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021121901 is an equidigital number, since it uses as much as digits as its factorization.

2021121901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 2021121901 is about 44956.8893608088. The cubic root of 2021121901 is about 1264.3408484081.

The spelling of 2021121901 in words is "two billion, twenty-one million, one hundred twenty-one thousand, nine hundred one".