401009981 has 2 divisors, whose sum is σ = 401009982. Its totient is φ = 401009980.

The previous prime is 401009963. The next prime is 401010007. The reversal of 401009981 is 189900104.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 285103225 + 115906756 = 16885^2 + 10766^2 .

It is a cyclic number.

It is not a de Polignac number, because 401009981 - 2¹⁰ = 401008957 is a prime.

It is a super-2 number, since 2×401009981² = 321618009723240722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401009911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200504990 + 200504991.

It is an arithmetic number, because the mean of its divisors is an integer number (200504991).

Almost surely, 2^401009981 is an apocalyptic number.

It is an amenable number.

401009981 is a deficient number, since it is larger than the sum of its proper divisors (1).

401009981 is an equidigital number, since it uses as much as digits as its factorization.

401009981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 401009981 is about 20025.2336066274. The cubic root of 401009981 is about 737.4259121592.

The spelling of 401009981 in words is "four hundred one million, nine thousand, nine hundred eighty-one".