20743905 has 72 divisors (see below), whose sum is σ = 42057792. Its totient is φ = 8701056.

The previous prime is 20743901. The next prime is 20743949. The reversal of 20743905 is 50934702.

It is not a de Polignac number, because 20743905 - 2² = 20743901 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20743901) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 124132 + ... + 124298.

It is an arithmetic number, because the mean of its divisors is an integer number (584136).

Almost surely, 2^20743905 is an apocalyptic number.

It is an amenable number.

20743905 is an abundant number, since it is smaller than the sum of its proper divisors (21313887).

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

20743905 is a wasteful number, since it uses less digits than its factorization.

20743905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 195 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 20743905 is about 4554.5477272722. The cubic root of 20743905 is about 274.7663249120.

The spelling of 20743905 in words is "twenty million, seven hundred forty-three thousand, nine hundred five".