1981946201 has 2 divisors, whose sum is σ = 1981946202. Its totient is φ = 1981946200.

The previous prime is 1981946167. The next prime is 1981946203. The reversal of 1981946201 is 1026491891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1674855625 + 307090576 = 40925^2 + 17524^2 .

It is a cyclic number.

It is not a de Polignac number, because 1981946201 - 2⁶ = 1981946137 is a prime.

It is a super-2 number, since 2×1981946201² = 7856221487316664802, which contains 22 as substring.

Together with 1981946203, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1981946203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990973100 + 990973101.

It is an arithmetic number, because the mean of its divisors is an integer number (990973101).

Almost surely, 2^1981946201 is an apocalyptic number.

It is an amenable number.

1981946201 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981946201 is an equidigital number, since it uses as much as digits as its factorization.

1981946201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 1981946201 is about 44519.0543587799. The cubic root of 1981946201 is about 1256.1185249370.

The spelling of 1981946201 in words is "one billion, nine hundred eighty-one million, nine hundred forty-six thousand, two hundred one".