631816 has 8 divisors (see below), whose sum is σ = 1184670. Its totient is φ = 315904.

The previous prime is 631789. The next prime is 631817. The reversal of 631816 is 618136.

It can be written as a sum of positive squares in only one way, i.e., 324900 + 306916 = 570^2 + 554^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (631817) by changing a digit.

631816 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39481 + ... + 39496.

2⁶³¹⁸¹⁶ is an apocalyptic number.

It is an amenable number.

631816 is a deficient number, since it is larger than the sum of its proper divisors (552854).

631816 is a wasteful number, since it uses less digits than its factorization.

631816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78983 (or 78979 counting only the distinct ones).

The product of its digits is 864, while the sum is 25.

The square root of 631816 is about 794.8685425905. The cubic root of 631816 is about 85.8084795187.

The spelling of 631816 in words is "six hundred thirty-one thousand, eight hundred sixteen".