630781 has 4 divisors (see below), whose sum is σ = 664000. Its totient is φ = 597564.

The previous prime is 630737. The next prime is 630797. The reversal of 630781 is 187036.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-630781 is a prime.

It is a super-2 number, since 2×630781² = 795769339922, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (630701) 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, 16581 + ... + 16618.

It is an arithmetic number, because the mean of its divisors is an integer number (166000).

2⁶³⁰⁷⁸¹ is an apocalyptic number.

It is an amenable number.

630781 is a deficient number, since it is larger than the sum of its proper divisors (33219).

630781 is a wasteful number, since it uses less digits than its factorization.

630781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33218.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 630781 is about 794.2172246936. The cubic root of 630781 is about 85.7615986147.

The spelling of 630781 in words is "six hundred thirty thousand, seven hundred eighty-one".