691686450 has 432 divisors, whose sum is σ = 2469841920. Its totient is φ = 137168640.

The previous prime is 691686449. The next prime is 691686487. The reversal of 691686450 is 54686196.

691686450 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×691686450² = 956860290227205000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 691686396 and 691686405.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 5446287 + ... + 5446413.

Almost surely, 2^691686450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691686450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1234920960).

691686450 is an abundant number, since it is smaller than the sum of its proper divisors (1778155470).

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

691686450 is a wasteful number, since it uses less digits than its factorization.

691686450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 176 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 691686450 is about 26299.9325094191. The cubic root of 691686450 is about 884.3749296824.

The spelling of 691686450 in words is "six hundred ninety-one million, six hundred eighty-six thousand, four hundred fifty".