684040651 has 4 divisors (see below), whose sum is σ = 781760752. Its totient is φ = 586320552.

The previous prime is 684040649. The next prime is 684040711. The reversal of 684040651 is 156040486.

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 684040651 - 2¹ = 684040649 is a prime.

It is a super-2 number, since 2×684040651² = 935823224441007602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684040601) 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, 48860040 + ... + 48860053.

It is an arithmetic number, because the mean of its divisors is an integer number (195440188).

Almost surely, 2^684040651 is an apocalyptic number.

684040651 is a deficient number, since it is larger than the sum of its proper divisors (97720101).

684040651 is an equidigital number, since it uses as much as digits as its factorization.

684040651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97720100.

The product of its (nonzero) digits is 23040, while the sum is 34.

The square root of 684040651 is about 26154.1708146139. The cubic root of 684040651 is about 881.1042658528.

The spelling of 684040651 in words is "six hundred eighty-four million, forty thousand, six hundred fifty-one".