20706840 has 320 divisors, whose sum is σ = 87816960. Its totient is φ = 4250880.

The previous prime is 20706823. The next prime is 20706869. The reversal of 20706840 is 4860702.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 249439 + ... + 249521.

It is an arithmetic number, because the mean of its divisors is an integer number (274428).

Almost surely, 2^20706840 is an apocalyptic number.

20706840 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 20706840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43908480).

20706840 is an abundant number, since it is smaller than the sum of its proper divisors (67110120).

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

20706840 is a wasteful number, since it uses less digits than its factorization.

20706840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 20706840 is about 4550.4768980844. The cubic root of 20706840 is about 274.6025774475.

The spelling of 20706840 in words is "twenty million, seven hundred six thousand, eight hundred forty".