202001981 has 4 divisors (see below), whose sum is σ = 207461532. Its totient is φ = 196542432.

The previous prime is 202001959. The next prime is 202001999. The reversal of 202001981 is 189100202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 82973881 + 119028100 = 9109^2 + 10910^2 .

It is a cyclic number.

It is not a de Polignac number, because 202001981 - 2²² = 197807677 is a prime.

It is a super-2 number, since 2×202001981² = 81609600655848722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (202001081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2729720 + ... + 2729793.

It is an arithmetic number, because the mean of its divisors is an integer number (51865383).

Almost surely, 2^202001981 is an apocalyptic number.

It is an amenable number.

202001981 is a deficient number, since it is larger than the sum of its proper divisors (5459551).

202001981 is an equidigital number, since it uses as much as digits as its factorization.

202001981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5459550.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 202001981 is about 14212.7400947178. The cubic root of 202001981 is about 586.7483488985.

The spelling of 202001981 in words is "two hundred two million, one thousand, nine hundred eighty-one".