401631 has 4 divisors (see below), whose sum is σ = 535512. Its totient is φ = 267752.

The previous prime is 401629. The next prime is 401651. The reversal of 401631 is 136104.

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

It is a cyclic number.

It is not a de Polignac number, because 401631 - 2¹ = 401629 is a prime.

It is a super-2 number, since 2×401631² = 322614920322, which contains 22 as substring.

It is a D-number.

401631 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 401631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (401651) 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, 66936 + ... + 66941.

It is an arithmetic number, because the mean of its divisors is an integer number (133878).

2⁴⁰¹⁶³¹ is an apocalyptic number.

401631 is a deficient number, since it is larger than the sum of its proper divisors (133881).

401631 is a wasteful number, since it uses less digits than its factorization.

401631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133880.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 401631 is about 633.7436390213. The cubic root of 401631 is about 73.7806384238.

Adding to 401631 its reverse (136104), we get a palindrome (537735).

The spelling of 401631 in words is "four hundred one thousand, six hundred thirty-one".