691036128 has 288 divisors, whose sum is σ = 2236066560. Its totient is φ = 201277440.

The previous prime is 691036117. The next prime is 691036141. The reversal of 691036128 is 821630196.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 691036092 and 691036101.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4401426 + ... + 4401582.

It is an arithmetic number, because the mean of its divisors is an integer number (7764120).

Almost surely, 2^691036128 is an apocalyptic number.

691036128 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691036128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1118033280).

691036128 is an abundant number, since it is smaller than the sum of its proper divisors (1545030432).

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

691036128 is a wasteful number, since it uses less digits than its factorization.

691036128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250 (or 239 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 691036128 is about 26287.5660341539. The cubic root of 691036128 is about 884.0976803536.

The spelling of 691036128 in words is "six hundred ninety-one million, thirty-six thousand, one hundred twenty-eight".