400646 has 4 divisors (see below), whose sum is σ = 600972. Its totient is φ = 200322.

The previous prime is 400643. The next prime is 400651. The reversal of 400646 is 646004.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100160 + ... + 100163.

It is an arithmetic number, because the mean of its divisors is an integer number (150243).

2⁴⁰⁰⁶⁴⁶ is an apocalyptic number.

400646 is a deficient number, since it is larger than the sum of its proper divisors (200326).

400646 is a wasteful number, since it uses less digits than its factorization.

400646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200325.

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 400646 is about 632.9660338438. The cubic root of 400646 is about 73.7202733782.

The spelling of 400646 in words is "four hundred thousand, six hundred forty-six".