20905434 has 48 divisors (see below), whose sum is σ = 52022880. Its totient is φ = 6000480.

The previous prime is 20905429. The next prime is 20905499. The reversal of 20905434 is 43450902.

It is a junction number, because it is equal to n+sod(n) for n = 20905398 and 20905407.

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, 984 + ... + 6540.

It is an arithmetic number, because the mean of its divisors is an integer number (1083810).

Almost surely, 2^20905434 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20905434, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26011440).

20905434 is an abundant number, since it is smaller than the sum of its proper divisors (31117446).

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

20905434 is a wasteful number, since it uses less digits than its factorization.

20905434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5595 (or 5592 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 20905434 is about 4572.2460563710. The cubic root of 20905434 is about 275.4776667963.

The spelling of 20905434 in words is "twenty million, nine hundred five thousand, four hundred thirty-four".