691020 has 72 divisors (see below), whose sum is σ = 2293200. Its totient is φ = 167040.

The previous prime is 691001. The next prime is 691037. The reversal of 691020 is 20196.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 690984 and 691002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1806 + ... + 2154.

It is an arithmetic number, because the mean of its divisors is an integer number (31850).

2⁶⁹¹⁰²⁰ is an apocalyptic number.

691020 is a gapful number since it is divisible by the number (60) 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 691020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1146600).

691020 is an abundant number, since it is smaller than the sum of its proper divisors (1602180).

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

691020 is a wasteful number, since it uses less digits than its factorization.

691020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375 (or 370 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 691020 is about 831.2761274089. The cubic root of 691020 is about 88.4090802354.

It can be divided in two parts, 69 and 1020, that added together give a square (1089 = 33²).

The spelling of 691020 in words is "six hundred ninety-one thousand, twenty".