684694890 has 256 divisors, whose sum is σ = 2149908480. Its totient is φ = 153216000.

The previous prime is 684694883. The next prime is 684694897. The reversal of 684694890 is 98496486.

It is an interprime number because it is at equal distance from previous prime (684694883) and next prime (684694897).

It is a super-2 number, since 2×684694890² = 937614184784224200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (684694897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 3584695 + ... + 3584885.

It is an arithmetic number, because the mean of its divisors is an integer number (8398080).

Almost surely, 2^684694890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 684694890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1074954240).

684694890 is an abundant number, since it is smaller than the sum of its proper divisors (1465213590).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

684694890 is a wasteful number, since it uses less digits than its factorization.

684694890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306 (or 300 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The square root of 684694890 is about 26166.6751804657. The cubic root of 684694890 is about 881.3850820544.

It can be divided in two parts, 684694 and 890, that added together give a square (685584 = 828²).

The spelling of 684694890 in words is "six hundred eighty-four million, six hundred ninety-four thousand, eight hundred ninety".