20809734 has 48 divisors (see below), whose sum is σ = 48275136. Its totient is φ = 5929600.

The previous prime is 20809729. The next prime is 20809757. The reversal of 20809734 is 43790802.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 20809695 and 20809704.

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, 18529 + ... + 19619.

It is an arithmetic number, because the mean of its divisors is an integer number (1005732).

Almost surely, 2^20809734 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20809734, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24137568).

20809734 is an abundant number, since it is smaller than the sum of its proper divisors (27465402).

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

20809734 is a wasteful number, since it uses less digits than its factorization.

20809734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1141 (or 1124 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 20809734 is about 4561.7687359181. The cubic root of 20809734 is about 275.0566671101.

The spelling of 20809734 in words is "twenty million, eight hundred nine thousand, seven hundred thirty-four".