20691000 has 288 divisors, whose sum is σ = 80917200. Its totient is φ = 4752000.

The previous prime is 20690993. The next prime is 20691001. The reversal of 20691000 is 19602.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20691001) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 1088991 + ... + 1089009.

Almost surely, 2^20691000 is an apocalyptic number.

20691000 is a gapful number since it is divisible by the number (20) 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 20691000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40458600).

20691000 is an abundant number, since it is smaller than the sum of its proper divisors (60226200).

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

20691000 is a wasteful number, since it uses less digits than its factorization.

20691000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68 (or 40 counting only the distinct ones).

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

The square root of 20691000 is about 4548.7360881898. The cubic root of 20691000 is about 274.5325391667.

The spelling of 20691000 in words is "twenty million, six hundred ninety-one thousand".