401601821 has 4 divisors (see below), whose sum is σ = 403164732. Its totient is φ = 400038912.

The previous prime is 401601799. The next prime is 401601833. The reversal of 401601821 is 128106104.

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 353853721 + 47748100 = 18811^2 + 6910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-401601821 is a prime.

It is a super-2 number, since 2×401601821² = 322568045261032082, 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 (401601881) 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, 781070 + ... + 781583.

It is an arithmetic number, because the mean of its divisors is an integer number (100791183).

Almost surely, 2^401601821 is an apocalyptic number.

It is an amenable number.

401601821 is a deficient number, since it is larger than the sum of its proper divisors (1562911).

401601821 is a wasteful number, since it uses less digits than its factorization.

401601821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1562910.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 401601821 is about 20040.0055139713. The cubic root of 401601821 is about 737.7885162831.

Adding to 401601821 its reverse (128106104), we get a palindrome (529707925).

The spelling of 401601821 in words is "four hundred one million, six hundred one thousand, eight hundred twenty-one".