20690406720 has 280 divisors, whose sum is σ = 74434674600. Its totient is φ = 5454839808.

The previous prime is 20690406673. The next prime is 20690406731. The reversal of 20690406720 is 2760409602.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 592240896 + 20098165824 = 24336^2 + 141768^2 .

It is a super-3 number, since 3×20690406720³ (a number of 32 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2302396 + ... + 2311364.

Almost surely, 2^20690406720 is an apocalyptic number.

20690406720 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 20690406720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37217337300).

20690406720 is an abundant number, since it is smaller than the sum of its proper divisors (53744267880).

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

20690406720 is an equidigital number, since it uses as much as digits as its factorization.

20690406720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9087 (or 9068 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The spelling of 20690406720 in words is "twenty billion, six hundred ninety million, four hundred six thousand, seven hundred twenty".