401801021 has 4 divisors (see below), whose sum is σ = 401926044. Its totient is φ = 401676000.

The previous prime is 401801017. The next prime is 401801027. The reversal of 401801021 is 120108104.

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 132480100 + 269320921 = 11510^2 + 16411^2 .

It is a cyclic number.

It is not a de Polignac number, because 401801021 - 2² = 401801017 is a prime.

It is a super-2 number, since 2×401801021² = 322888120953284882, 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 (401801027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57560 + ... + 64161.

It is an arithmetic number, because the mean of its divisors is an integer number (100481511).

Almost surely, 2^401801021 is an apocalyptic number.

It is an amenable number.

401801021 is a deficient number, since it is larger than the sum of its proper divisors (125023).

401801021 is a wasteful number, since it uses less digits than its factorization.

401801021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125022.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 401801021 is about 20044.9749563326. The cubic root of 401801021 is about 737.9104805208.

Adding to 401801021 its reverse (120108104), we get a palindrome (521909125).

The spelling of 401801021 in words is "four hundred one million, eight hundred one thousand, twenty-one".